SSAT Upper Level Reading : Inferences and Predictions in Narrative Science Passages

Study concepts, example questions & explanations for SSAT Upper Level Reading

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Example Questions

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Example Question #1 : Making Inferences About The Author Or Natural Science Passage Content

Adapted from COMMON DISEASES OF FARM ANIMALS (1915) by R. A. Craig

The common bot-fly of the horse (G. equi) has a heavy, hairy body. Its color is brown, with dark and yellowish spots. The female fly can be seen during the warm weather, hovering around the horse, and darting toward the animal for the purpose of depositing the egg. The color of the egg is yellow, and it adheres firmly to the hair. It hatches in from two to four weeks, and the larva reaches the mouth through the animal licking the part. From the mouth, it passes to the stomach, where it attaches itself to the gastric mucous membrane. Here it remains until fully developed, when it becomes detached and is passed out with the faeces. The third stage is passed in the ground. This takes place in the spring and early summer and lasts for several weeks, when it finally emerges a mature fly.

The bot-fly of the ox (H. lineata) is dark in color and about the size of a honey-bee. On warm days, the female may be seen depositing eggs on the body of the animal, especially in the region of the heels. This seems to greatly annoy the animal, and it is not uncommon for cattle to become stampeded. The egg reaches the mouth through the animal licking the part. The saliva dissolves the shell of the egg and the larva is freed. It then migrates from the gullet, wanders about in the tissue until finally it may reach a point beneath the skin of the back. Here the larva matures and forms the well-known swelling or warble. In the spring of the year it works out through the skin. The next stage is spent in the ground. The pupa state lasts several weeks, when the mature fly issues forth.

The bot-fly of sheep (O. ovis) resembles an overgrown house-fly. Its general color is brown, and it is apparently lazy, flying about very little. This bot-fly makes its appearance when the warm weather begins, and deposits live larvae in the nostrils of sheep. This act is greatly feared by the animals, as shown by their crowding together and holding the head down. The larva works up the nasal cavities and reaches the sinuses of the head, where it becomes attached to the lining mucous membrane. In the spring, when fully developed, it passes out through the nasal cavities and nostrils, drops to the ground, buries itself, and in from four to six weeks develops into the mature fly.

SYMPTOMS OF BOT-FLY DISEASES.—The larvae of the bot-fly of the horse do not cause characteristic symptoms of disease. Work horses that are groomed daily are not hosts for a large number of "bots," but young and old horses that are kept in a pasture or lot and seldom groomed may become unthrifty and "pot bellied," or show symptoms of indigestion.

Cattle suffer much pain from the development of the larva of the H. lineata. During the spring of the year, the pain resulting from the presence of the larvae beneath the skin and the penetration of the skin is manifested by excitement and running about. Besides the loss in milk and beef production, there is a heavy yearly loss from the damage to hides.

The life of the bot-fly of sheep results in a severe catarrhal inflammation of the mucous membrane lining the sinuses of the head, and a discharge of a heavy, pus-like material from the nostrils. The irritation produced by the larvae may be so serious at times as to result in nervous symptoms and death.

It can reasonably be inferred from the passage that __________.

Possible Answers:

bot-flies are never lethal

bot-flies do not trouble the leather trade

bot-flies live in hot countries

bot-flies are parasitic insects

bot-flies are beneficial to horses

Correct answer:

bot-flies are parasitic insects

Explanation:

We can tell that from the description of these flies as being reliant upon other animals' bodies that they are parasitic in their larval stage. The definition of a "parasite" is an animal which lives on or in another animal to get food or protection.

Example Question #1 : Making Inferences About The Author Or Natural Science Passage Content

Adapted from The Evolutionist at Large by Grant Allen (1881)

I am engaged in watching a brigade of ants out on foraging duty, and intent on securing for the nest three whole segments of a deceased earthworm. They look for all the world like those busy companies one sees in the Egyptian wall paintings, dragging home a huge granite colossus by sheer force of bone and sinew. Every muscle in their tiny bodies is strained to the utmost as they pry themselves laboriously against the great boulders that strew the path, and that are known to our Brobdingnagian intelligence as grains of sand. Besides the workers themselves, a whole battalion of stragglers runs to and fro upon the broad line that leads to the headquarters of the community. The province of these stragglers, who seem so busy doing nothing, probably consists in keeping communications open, and encouraging the sturdy pullers by occasional relays of fresh workmen. I often wish that I could for a while get inside those tiny brains, and see, or rather smell, the world as ants do. For there can be little doubt that to these brave little carnivores here the universe is chiefly known as a collective bundle of odors, simultaneous or consecutive. As our world is mainly a world of visible objects, theirs, I believe, is mainly a world of olfactible things.

In the head of every one of these little creatures is something that we may fairly call a brain. Of course most insects have no real brains; the nerve-substance in their heads is a mere collection of ill-arranged ganglia, directly connected with their organs of sense. Whatever man may be, an earwig at least is a conscious, or rather a semi-conscious, automaton. He has just a few knots of nerve cells in his little pate, each of which leads straight from his dim eye or his vague ear or his indefinite organs of taste; and his muscles obey the promptings of external sensations without possibility of hesitation or consideration, as mechanically as the valve of a steam engine obeys the governor balls. The poor soul's intellect is wholly deficient, and the senses alone make up all that there is of him, subjectively considered. But it is not so with the highest insects. They have something that truly answers to the real brain of men, apes, and dogs, to the cerebral hemispheres and the cerebellum that are superadded in us mammals upon the simple sense-centers of lower creatures. Besides the eye, with its optic nerve and optic perceptive organs—besides the ear, with its similar mechanism—we mammalian lords of creation have a higher and more genuine brain, that collects and compares the information given to the senses, and sends down the appropriate messages to the muscles accordingly. Now, bees and flies and ants have got much the same sort of arrangement, on a smaller scale, within their tiny heads. On top of the little knots that do duty as nerve centers for their eyes and mouths, stand two stalked bits of nervous matter, whose duty is analogous to that of our own brains. And that is why these three sorts of insects think and reason so much more intellectually than beetles or butterflies, and why the larger part of them have organized their domestic arrangements on such an excellent cooperative plan.

We know well enough what forms the main material of thought with bees and flies, and that is visible objects. For you must think about something if you think at all; and you can hardly imagine a contemplative blow-fly setting itself down to reflect, like a Hindu devotee, on the syllable Om, or on the oneness of existence. Abstract ideas are not likely to play a large part in apian consciousness. A bee has a very perfect eye, and with this eye it can see not only form, but also color, as Sir John Lubbock's experiments have shown us. The information that it gets through its eye, coupled with other ideas derived from touch, smell, and taste, no doubt makes up the main thinkable and knowable universe as it reveals itself to the apian intelligence. To ourselves and to bees alike the world is, on the whole, a colored picture, with the notions of distance and solidity thrown in by touch and muscular effort; but sight undoubtedly plays the first part in forming our total conception of things generally.

It can reasonably be inferred from the passage that __________.

Possible Answers:

beetles and butterflies have the same types of brains as ants

religious influences can be ascribed to insects

bees and flies are visually stimulated

the author believes that ants have the ability to consider their actions

the author is more fond of bees and flies than ants

Correct answer:

bees and flies are visually stimulated

Explanation:

The author suggests that bees and flies are visually stimulated in the third paragraph when he states that “We know well enough what forms the main material of thought with bees and flies, and that is visible objects.” In the second paragraph, the author suggests that beetles and butterflies do not have the same types of brains as ants. That the author likes bees and flies more than ants, the idea of ascribing religious influences to insects, and the idea that insects consider their actions are not mentioned or are stated as being false by the text.

Example Question #82 : Content Of Natural Science Passages

Adapted from Ice-Caves of France and Switzerland by George Forrest Browne (1865)

This account states that the cave is in the county of Thorn, among the lowest spurs of the Carpathians. The entrance, which faces the north, and is exposed to the cold winds from the snowy part of the Carpathian range, is eighteen fathoms high and nine broad; and the cave spreads out laterally, and descends to a point fifty fathoms below the entrance, where it is twenty-six fathoms in breadth, and of irregular height. Beyond this no one had at that time penetrated, on account of the unsafe footing, although many distant echoes were returned by the farther recesses of the cave; indeed, to get even so far as this, much step-cutting was necessary.

When the external frost of winter comes on, the account proceeds, the effect in the cave is the same as if fires had been lighted there: the ice melts, and swarms of flies and bats and hares take refuge in the interior from the severity of the winter. As soon as spring arrives, the warmth of winter disappears from the interior, water exudes from the roof and is converted into ice, while the more abundant supplies which pour down on to the sandy floor are speedily frozen there. In the dog-days, the frost is so intense that a small icicle becomes in one day a huge mass of ice; but a cool day promptly brings a thaw, and the cave is looked upon as a barometer, not merely feeling, but also presaging, the changes of weather. The people of the neighborhood, when employed in field-work, arrange their labour so that the mid-day meal may be taken near the cave, when they either ice the water they have brought with them, or drink the melted ice, which they consider very good for the stomach. It had been calculated that six hundred weekly carts would not be sufficient to keep the cavern free from ice. The ground above the cave is peculiarly rich in grass.

In explanation of these phenomena, Bell threw out the following suggestions, which need no comment. The earth being of itself cold and damp, the external heat of the atmosphere, by partially penetrating into the ground, drives in this native cold to the inner parts of the earth, and makes the cold there more dense. On the other hand, when the external air is cold, it draws forth towards the surface the heat there may be in the inner part of the earth, and thus makes caverns warm. In support and illustration of this view, he states that in the hotter parts of Hungary, when the people wish to cool their wine, they dig a hole two feet deep, and place in it the flagon of wine, and, after filling up the hole again, light a blazing fire upon the surface, which cools the wine as if the flagon had been laid in ice. He also suggests that possibly the cold winds from the Carpathians bring with them imperceptible particles of snow, which reach the water of the cave, and convert it into ice. Further, the rocks of the Carpathians abound in salts, nitre, alum, etc., which may, perhaps, mingle with such snowy particles, and produce the ordinary effect of the snow and salt in the artificial production of ice.

It can reasonably be inferred from the passage that __________.

Possible Answers:

the cave is in Hungary

the cave is high in the mountains

the ice is unsanitary

the author does not respect Bell's opinion

the cave is not far from civilization

Correct answer:

the cave is not far from civilization

Explanation:

We can infer that because the villagers' work is near the cave in summer and they use the cave's ice, there is some form of civilization in proximity to the cave. We know from the villager's use of the ice to melt it into water to drink that it is unlikely to be unsanitary. Bell's opinion is not commented on and is therefore, in the opinion of the author, possibly correct. The cave is in the country of Thorn and is at the base of the Carpathian Mountains, as is stated in the first paragraph.  

Example Question #1 : Inferences And Predictions In Narrative Science Passages

Adapted from Rambles in the Mammoth Cave, during the Year 1844 by Alexander Clark Bullitt (1845)

Pensico Avenue averages about fifty feet in width with a height of about thirty feet, and is said to be two miles long. It unites in an eminent degree the truly beautiful with the sublime, and is highly interesting throughout its entire extent. For a quarter of a mile from the entrance, the roof is beautifully arched, about twelve feet high and sixty wide, and formerly was encrusted with rosettes and other formations, nearly all of which have been taken away or demolished, leaving this section of the Cave quite denuded. The walking here is excellent; a dozen persons might run abreast for a quarter of a mile to Bunyan's Way, a branch of the avenue leading on to the river. At this point the avenue changes its features of beauty and regularity, for those of wild grandeur and sublimity, which it preserves to the end. The way, no longer smooth and level, is frequently interrupted and turned aside by huge rocks, which lie tumbled around in all imaginable disorder. The roof now becomes very lofty and imposingly magnificent; its long, pointed, or lancet arches, forcibly reminding you of the rich and gorgeous ceilings of the old Gothic cathedrals, at the same time solemnly impressing you with the conviction that this is a "building not made with hands." No one, not dead to all the more refined sensibilities of our nature, but must exclaim, in beholding the sublime scenes which here present themselves, this is not the work of man! No one can be here without being reminded of the all pervading presence of the great "Father of all."

"What, but God, pervades, adjusts and agitates the whole!"

Not far from the point at which the avenue assumes the rugged features, which now characterize it, we separated from our guide, he continuing his straight-forward course, and we descending gradually a few feet and entering a tunnel of fifteen feet wide on our left, the ceiling twelve or fourteen feet high, perfectly arched and beautifully covered with white incrustations, very soon reached the Great Crossings. Here the guide jumped down some six or eight feet from the avenue which we had left, into the tunnel where we were standing, and crossing it, climbed up into the avenue, which he pursued for a short distance or until it united with the tunnel, where he again joined us. In separating from, then crossing, and again uniting with the avenue, it describes with it something like the figure 8. The name, “Great Crossings,” is not unapt. It was however, not given, as our intelligent guide veritably assured us, in honor of the Great Crossings where the man lives who killed Tecumseh, but because two great caves cross here; and moreover said he, "the valiant Colonel ought to change the name of his place, as no two places in a state should bear the same name, and this being the great place ought to have the preference."

Not very far from this point, we ascended a hill on our left, and walking a short distance over our shoe-tops in dry nitrous earth in a direction somewhat at a right angle with the avenue below, we arrived at the Pine Apple Bush, a large column composed of a white, soft, crumbling material, with bifurcations extending from the floor to the ceiling. At a short distance, either to the right or left, you have a fine view of the avenue some twenty feet below, both up and down. Why this crumbling stalactite is called the Pine Apple Bush, I cannot divine. It stands however in a charming, secluded spot, inviting to repose; and we luxuriated in inhaling the all-inspiring air, while reclining on the clean, soft, and dry saltpeter earth.

What is the main idea of the phrase “a dozen persons might run abreast for a quarter of a mile”?

Possible Answers:

Various people would have no difficulty in traversing this part of the cave in succession.

Several people may sprint in a column for a considerable distance.

The footing is easy going on the left side of the cave for a quarter of a mile.

Despite the difficult footing numerous people could make their way along the cave with ease.

Twelve people running in a row could go for a considerable distance along the cave. 

Correct answer:

Twelve people running in a row could go for a considerable distance along the cave. 

Explanation:

To answer this question, it must be inferred that “a dozen persons” is twelve people and that to “run abreast” is to run alongside one another or to run in a row. If this has been correctly inferred, then the correct answer is easily chosen. The correct answer can also be inferred from the passage, as the author is suggesting that the ground is level and wide. The first and fourth answers suggest that the people would be running one behind the other, which negates the width of this part of the cave as suggested by the author. The answer choice "The footing is easy going on the left side of the cave for a quarter of a mile" is wrong, as it suggests only one side of the cave is easily run on, whilst the answer choice "Despite the difficult footing numerous people could make their way along the cave with ease" suggests that the ground is unsuitable for running.  

Example Question #1 : Making Inferences In Narrative Science Passages

Adapted from Rambles in the Mammoth Cave, during the Year 1844 by Alexander Clark Bullitt (1845)

Pensico Avenue averages about fifty feet in width with a height of about thirty feet, and is said to be two miles long. It unites in an eminent degree the truly beautiful with the sublime, and is highly interesting throughout its entire extent. For a quarter of a mile from the entrance, the roof is beautifully arched, about twelve feet high and sixty wide, and formerly was encrusted with rosettes and other formations, nearly all of which have been taken away or demolished, leaving this section of the Cave quite denuded. The walking here is excellent; a dozen persons might run abreast for a quarter of a mile to Bunyan's Way, a branch of the avenue leading on to the river. At this point the avenue changes its features of beauty and regularity, for those of wild grandeur and sublimity, which it preserves to the end. The way, no longer smooth and level, is frequently interrupted and turned aside by huge rocks, which lie tumbled around in all imaginable disorder. The roof now becomes very lofty and imposingly magnificent; its long, pointed, or lancet arches, forcibly reminding you of the rich and gorgeous ceilings of the old Gothic cathedrals, at the same time solemnly impressing you with the conviction that this is a "building not made with hands." No one, not dead to all the more refined sensibilities of our nature, but must exclaim, in beholding the sublime scenes which here present themselves, this is not the work of man! No one can be here without being reminded of the all pervading presence of the great "Father of all."

"What, but God, pervades, adjusts and agitates the whole!"

Not far from the point at which the avenue assumes the rugged features, which now characterize it, we separated from our guide, he continuing his straight-forward course, and we descending gradually a few feet and entering a tunnel of fifteen feet wide on our left, the ceiling twelve or fourteen feet high, perfectly arched and beautifully covered with white incrustations, very soon reached the Great Crossings. Here the guide jumped down some six or eight feet from the avenue which we had left, into the tunnel where we were standing, and crossing it, climbed up into the avenue, which he pursued for a short distance or until it united with the tunnel, where he again joined us. In separating from, then crossing, and again uniting with the avenue, it describes with it something like the figure 8. The name, “Great Crossings,” is not unapt. It was however, not given, as our intelligent guide veritably assured us, in honor of the Great Crossings where the man lives who killed Tecumseh, but because two great caves cross here; and moreover said he, "the valiant Colonel ought to change the name of his place, as no two places in a state should bear the same name, and this being the greatplace ought to have the preference."

Not very far from this point, we ascended a hill on our left, and walking a short distance over our shoe-tops in dry nitrous earth in a direction somewhat at a right angle with the avenue below, we arrived at the Pine Apple Bush, a large column composed of a white, soft, crumbling material, with bifurcations extending from the floor to the ceiling. At a short distance, either to the right or left, you have a fine view of the avenue some twenty feet below, both up and down. Why this crumbling stalactite is called the Pine Apple Bush, I cannot divine. It stands however in a charming, secluded spot, inviting to repose; and we luxuriated in inhaling the all-inspiring air, while reclining on the clean, soft, and dry saltpeter earth.

It can reasonably be inferred from the passage that __________.

Possible Answers:

The author believes in a deity. 

The nitrous earth was dangerous.

It was obvious why the Pine Apple Bush was given its name.

The author was unaffected by the cave system.

The guide is unfamiliar with the state the cave system is in.

Correct answer:

The author believes in a deity. 

Explanation:

We can infer from the author's exclamations about God or the “Father of all” in the first paragraph, which are made with seriousness, that the author probably believes in a god or a deity. We can reach this conclusion by eliminating all of the other answer choices, which are all equally false according to the passage.

Example Question #51 : Content Of Natural Science Passages

Adapted from Common Diseases of Farm Animals by R. A. Craig (1916, 2nd ed.)

The common bot-fly of the horse (G. equi) has a heavy, hairy body. Its color is brown, with dark and yellowish spots. The female fly can be seen during the warm weather, hovering around the horse, and darting toward the animal for the purpose of depositing the egg. The color of the egg is yellow, and it adheres firmly to the hair. It hatches in from two to four weeks, and the larva reaches the mouth through the animal licking the part. From the mouth, it passes to the stomach, where it attaches itself to the gastric mucous membrane. Here it remains until fully developed, when it becomes detached and is passed out with the feces. The third stage is passed in the ground. This takes place in the spring and early summer and lasts for several weeks, when it finally emerges a mature fly.

The bot-fly of the ox (H. lineata) is dark in color and about the size of a honey-bee. On warm days, the female may be seen depositing eggs on the body of the animal, especially in the region of the heels. This seems to greatly annoy the animal, and it is not uncommon for cattle to become stampeded. The egg reaches the mouth through the animal licking the part. The saliva dissolves the shell of the egg and the larva is freed. It then migrates from the gullet, wanders about in the tissue until finally it may reach a point beneath the skin of the back. Here the larva matures and forms the well-known swelling or warble. In the spring of the year it works out through the skin. The next stage is spent in the ground. The pupa state lasts several weeks, when the mature fly issues forth.

The bot-fly of sheep (O. ovis) resembles an overgrown house-fly. Its general color is brown, and it is apparently lazy, flying about very little. This bot-fly makes its appearance when the warm weather begins, and deposits live larvae in the nostrils of sheep. This act is greatly feared by the animals, as shown by their crowding together and holding the head down. The larva works up the nasal cavities and reaches the sinuses of the head, where it becomes attached to the lining mucous membrane. In the spring, when fully developed, it passes out through the nasal cavities and nostrils, drops to the ground, buries itself, and in from four to six weeks develops into the mature fly.

SYMPTOMS OF BOT-FLY DISEASES.—The larvae of the bot-fly of the horse do not cause characteristic symptoms of disease. Work horses that are groomed daily are not hosts for a large number of "bots," but young and old horses that are kept in a pasture or lot and seldom groomed may become unthrifty and "pot bellied," or show symptoms of indigestion.

Cattle suffer much pain from the development of the larva of the H. lineata. During the spring of the year, the pain resulting from the presence of the larvae beneath the skin and the penetration of the skin is manifested by excitement and running about. Besides the loss in milk and beef production, there is a heavy yearly loss from the damage to hides.

The life of the bot-fly of sheep results in a severe catarrhal inflammation of the mucous membrane lining the sinuses of the head, and a discharge of a heavy, pus-like material from the nostrils. The irritation produced by the larvae may be so serious at times as to result in nervous symptoms and death.

The fifth paragraph states that which of the following is true?

Possible Answers:

O. ovis larvae break out through the cow’s skin.

Bot-flies can be financially crippling to a farmer. 

Bot-fly larvae emerge in the summer months.

Cattle are not susceptible to the results of an infestation of bot-fly larvae.

A bot-fly infestation makes cows lethargic.

Correct answer:

Bot-flies can be financially crippling to a farmer. 

Explanation:

We can infer that an infestation of bot-fly larvae in cattle is financially crippling to a farmer, as it says that meat, milk and hide production can be affected. This would result in a farmer making less money from his animals.

Example Question #21 : Making Inferences About The Author Or Natural Science Passage Content

"Cacti" by Ami Dave (2013)

Cacti are plants suited to the desert, and we must always keep this factor in mind when growing ornamental cacti in our gardens, for it helps us provide cacti with conditions that allow them to survive and thrive. For example, a cactus should never be watered over its body, as it will start to rot. This is because it is covered with a waxy coating which prevents water loss through evaporation. When one waters the cactus over its body, the waxy coating is washed away and the plant begins to rot. The amount of water that one must supply to the cactus is very much dependent upon the season and upon the climate of the place. During the summer season one should water cacti every four days, whereas in the rainy season, once every fifteen days is quite enough.

Cacti need a minimum of two and a half hours of sunlight per day; however, they should not be kept in the sun all day because they may wrinkle when exposed to too much bright sunlight. Unlike other plants, cacti produce carbon dioxide during the day and oxygen during the night, so they are ideal plants to be kept in bedrooms to freshen up the air at night.

If a cactus is to thrive and prosper, the size of the pot in which it is grown needs to be monitored carefully. The pot should always be a little smaller than the plant itself because it is only when the plant has to struggle to survive that it will thrive. If the pot is too spacious and the plant does not need to struggle, chances are that the cactus will die. Similarly, if a cactus shows no signs of growth, stop watering it. Watering should be resumed only when the plant begins to grow again.

The substrata of a cactus pot is ideally composed of pieces of broken bricks at the bottom, followed by a layer of charcoal above the bricks, and then coarse sand and pebbles above the charcoal. Leaf mould is the best manure.

Grafting cacti is very simple. A very small piece of the cactus plant should be stuck with tape to the plant that needs grafting. The smaller the piece, the easier it is to graft. To reproduce cacti, one has to simply cut off a piece of the cactus, allow it to dry for a few days, and then place it over the cacti substrate. It will automatically develop roots.

It is very easy to differentiate between cacti and other plants that look like cacti. All cacti have fine hair at the base of each thorn. The so-called “thorns” are in fact highly modified leaves which prevent loss of water through transpiration. If one ever gets pricked by cacti thorns, one should take tape, place it over the area where the thorns have penetrated the skin, and then peel it off. All of the thorns will get stuck to the tape and will be removed.

The passage is most likely an excerpt from what type of document?

Possible Answers:

A manual about how to grow cacti at home

A science textbook

A personal anecdote about cacti 

A descriptive panel at a botanical garden

An informational brochure

Correct answer:

A manual about how to grow cacti at home

Explanation:

It most likely comes from a how-to manual, since it outlines the steps for planting and nurturing a cactus as it grows. A brochure would not contain quite as much information, and would not be detailed. A botanical garden would address the lineage of the plant and more about its genus and species, rather than how to grow it. A science textbook would explore the scientific analysis of the plant, such as how it obtains energy through photosynthesis and more facts along those lines. A personal anecdote about cacti would not need to give any information about how to grow one.

Example Question #1 : Making Inferences In Narrative Science Passages

"Cacti" by Ami Dave (2013)

Cacti are plants suited to the desert, and we must always keep this factor in mind when growing ornamental cacti in our gardens, for it helps us provide cacti with conditions that allow them to survive and thrive. For example, a cactus should never be watered over its body, as it will start to rot. This is because it is covered with a waxy coating which prevents water loss through evaporation. When one waters the cactus over its body, the waxy coating is washed away and the plant begins to rot. The amount of water that one must supply to the cactus is very much dependent upon the season and upon the climate of the place. During the summer season one should water cacti every four days, whereas in the rainy season, once every fifteen days is quite enough.

Cacti need a minimum of two and a half hours of sunlight per day; however, they should not be kept in the sun all day because they may wrinkle when exposed to too much bright sunlight. Unlike other plants, cacti produce carbon dioxide during the day and oxygen during the night, so they are ideal plants to be kept in bedrooms to freshen up the air at night.

If a cactus is to thrive and prosper, the size of the pot in which it is grown needs to be monitored carefully. The pot should always be a little smaller than the plant itself because it is only when the plant has to struggle to survive that it will thrive. If the pot is too spacious and the plant does not need to struggle, chances are that the cactus will die. Similarly, if a cactus shows no signs of growth, stop watering it. Watering should be resumed only when the plant begins to grow again.

The substrata of a cactus pot is ideally composed of pieces of broken bricks at the bottom, followed by a layer of charcoal above the bricks, and then coarse sand and pebbles above the charcoal. Leaf mould is the best manure.

Grafting cacti is very simple. A very small piece of the cactus plant should be stuck with tape to the plant that needs grafting. The smaller the piece, the easier it is to graft. To reproduce cacti, one has to simply cut off a piece of the cactus, allow it to dry for a few days, and then place it over the cacti substrate. It will automatically develop roots.

It is very easy to differentiate between cacti and other plants that look like cacti. All cacti have fine hair at the base of each thorn. The so-called “thorns” are in fact highly modified leaves which prevent loss of water through transpiration. If one ever gets pricked by cacti thorns, one should take tape, place it over the area where the thorns have penetrated the skin, and then peel it off. All of the thorns will get stuck to the tape and will be removed.

Which of the following can be inferred from the information provided in the passage?

Possible Answers:

Cacti follow a respiration cycle that is different than that of other plants.

Pot size is not an important factor in cactus growth.

It is difficult to distinguish cacti from other plants.

People have been growing cacti in their homes for hundreds of years.

Cacti are found in every desert known to man.

Correct answer:

Cacti follow a respiration cycle that is different than that of other plants.

Explanation:

The second paragraph states that, unlike other plants, cacti produce CO2 during the day and O2 during the night, making them good plants to freshen the air when one is sleeping. Thus, it can be inferred that cacti have a unique respiration cycle, compared to other plants. The other answer choices are not inferences that can be made from the passage. The passage states that pot size is indeed a factor is growth, and the last paragraph mentions how it is easy to tell cacti apart from other plants. While the passage does mention that the cactus is a desert plant, nowhere does it say that cacti are found in EVERY desert. Similarly, the passage provides no information about for how long people have been growing cacti in their homes.

Example Question #161 : Natural Science Passages

Adapted from An Introduction to Astronomy by Forest Ray Moulton (1916 ed.)

It is doubtful if any important scientific idea ever sprang suddenly into the mind of a single man. The great intellectual movements in the world have had long periods of preparation, and often many men were groping for the same truth, without exactly seizing it, before it was fully comprehended.

The foundation on which all science rests is the principle that the universe is orderly, and that all phenomena succeed one another in harmony with invariable laws. Consequently, science was impossible until the truth of this principle was perceived, at least as applied to a limited part of nature.

The phenomena of ordinary observation, as, for example, the weather, depend on such a multitude of factors that it was not easy for men in their primitive state to discover that they occur in harmony with fixed laws. This was the age of superstition, when nature was supposed to be controlled by a great number of capricious gods whose favor could be won by childish ceremonies. Enormous experience was required to dispel such errors and to convince men that the universe is one vast organization whose changes take place in conformity with laws which they can in no way alter.

The actual dawn of science was in prehistoric times, probably in the civilizations that flourished in the valleys of the Nile and the Euphrates. In the very earliest records of these people that have come down to modern times it is found that they were acquainted with many astronomical phenomena and had coherent ideas with respect to the motions of the sun, moon, planets, and stars. It is perfectly clear from their writings that it was from their observations of the heavenly bodies that they first obtained the idea that the universe is not a chaos. Day and night were seen to succeed each other regularly, the moon was found to pass through its phases systematically, the seasons followed one another in order, and in fact the more conspicuous celestial phenomena were observed to occur in an orderly sequence. It is to the glory of astronomy that it first led men to the conclusion that law reigns in the universe.

Based on the author’s words, what could we say about the discoveries of Newton or Galileo, whom many consider to be geniuses far greater than most other scientists in history?

Possible Answers:

None of the other answers

Their work must be seen in a broader context of scientific history.

They were the first to notice the orderliness of celestial motion.

Their work came forth uniquely and suddenly, like Athena from the brow of Zeus.

Their work was revolutionary, overturning the results of almost every previous finding.

Correct answer:

Their work must be seen in a broader context of scientific history.

Explanation:

The very topic sentence of the first paragraph is all that is needed to answer this question correctly. Almost all scientific advances have been prepared by the work of many hands, and while some one person might have undertaken pivotal experiments, it should not be believe to have sprung directly from that one person alone. Hence, even though Galileo, Newton, and others are quite unique in their influence, they are not the sole sources of scientific thought.

Example Question #11 : Making Inferences About The Author Or Natural Science Passage Content

Adapted from An Introduction to Astronomy by Forest Ray Moulton (1916 ed.)

It is doubtful if any important scientific idea ever sprang suddenly into the mind of a single man. The great intellectual movements in the world have had long periods of preparation, and often many men were groping for the same truth, without exactly seizing it, before it was fully comprehended.

The foundation on which all science rests is the principle that the universe is orderly, and that all phenomena succeed one another in harmony with invariable laws. Consequently, science was impossible until the truth of this principle was perceived, at least as applied to a limited part of nature.

The phenomena of ordinary observation, as, for example, the weather, depend on such a multitude of factors that it was not easy for men in their primitive state to discover that they occur in harmony with fixed laws. This was the age of superstition, when nature was supposed to be controlled by a great number of capricious gods whose favor could be won by childish ceremonies. Enormous experience was required to dispel such errors and to convince men that the universe is one vast organization whose changes take place in conformity with laws which they can in no way alter.

The actual dawn of science was in prehistoric times, probably in the civilizations that flourished in the valleys of the Nile and the Euphrates. In the very earliest records of these people that have come down to modern times it is found that they were acquainted with many astronomical phenomena and had coherent ideas with respect to the motions of the sun, moon, planets, and stars. It is perfectly clear from their writings that it was from their observations of the heavenly bodies that they first obtained the idea that the universe is not a chaos. Day and night were seen to succeed each other regularly, the moon was found to pass through its phases systematically, the seasons followed one another in order, and in fact the more conspicuous celestial phenomena were observed to occur in an orderly sequence. It is to the glory of astronomy that it first led men to the conclusion that law reigns in the universe.

Which of the following would be compatible with the underlined sentence?

Possible Answers:

Without the Egyptians, science would likely have never developed.

The chaos found in most ancient legends precluded any development of scientific knowledge.

From the chaos of many facts, science arises when one great mind surveys the details in a new manner.

None of the other answers

We might mark the start of scientific history with the first time that two cavemen realized that they could always make fire by means of a certain process of rubbing sticks.

Correct answer:

We might mark the start of scientific history with the first time that two cavemen realized that they could always make fire by means of a certain process of rubbing sticks.

Explanation:

"The foundation on which all science rests is the principle that the universe is orderly, and that all phenomena succeed one another in harmony with invariable laws."

The underlined sentence states that the foundation of science is the realization that there is an orderliness in the world.  While we cannot say for certain how this dawned on the human race (and then was handed down), a good example of such a realization would be found in the case of cavemen realizing that fire does indeed arise from a regular ordering of causes. Seeing this regularity, they would have the startings of scientific knowledge.

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