When something is dismal such as a dismal day, it means that it is bleak or desolate.

The word "extinct" refers to species of living things and means no longer existing or gone. "Gone" is the best choice because it is part of the definiton of "extinct."

When a process is "automated," it is done by a machine instead of by a human. "Mechanized" also refers to procedures that are completed by machines. If you have trouble remembering these words, just think about how a machine (a similar word that you likely know) is automatic. "Personalized" has a very different meaning; it means changed to fit an individual's unique needs. "Bland" means tasteless, and "reckless" means careless or willing to do dangerous things without worrying about the consequences.

Residual means left over or left behind. For example, I noticed some residual dirt on some of the dishes when I was taking them out of the dishwasher.

"Unexpected" is an adjective that means not expected. So, the answer choice closest in meaning to "unexpected" is "surprising," an adjective that means unexpected. None of the other answers are close in meaning to "unexpected": "gradual" means slowly taking place; "bold" means confident and courageous; and "brash" means assertive in a rude way.

"Destructive" means causing damage. Ruinous also means disastrous or causing damage, so "ruinous" is the correct answer. As for the other answer choices, "considerable" means noticeable due to large size or amount, "brief" means short or quick, a "frontier" is a border between two countries, and to "boast" means to talk about yourself and your achievements with pride.

"Damaging" means harmful or causing damage. To further help you, "considerate" means thoughtful about other people’s feelings; "inconsiderate" means unkind and not caring; "applicable" means able to be applied to or relevant. 

When we say that something is "in peril" or "imperiled," that thing is in a state of great danger or risk. The word "perilous" is the adjective that describes such a state ("a perilous situation"). Perilous situations are likely to be very frightening or even terrifying. However, these words really indicate what perilous things emotionally cause. They do not describe what it is to be perilous. "To be perilous" means to be very dangerous. Therefore, the best option is "hazardous." A "hazard" is a danger or a source of danger. "Hazardous" describes something that is dangerous.

The word "fatal" is related to the word "fate," which indicates the idea that something is meant to happen. However, "fatal" indicates a particular kind of "fated" occurrence, namely death. Things that happen by "fate" often are ominous or threatening. A "fatal" wound is one that is likely to kill. Therefore, the best synonyms will reflect either complete destruction or the causing of death. While something that is fatal might be depressing, something that is depressing really is not deadly (at least, not necessarily). The two words describe two different things. The best option is "deadly," meaning likely to kill.

When we "prohibit" something, we ban it or forbid it from being done. "Prohibited substances" are things that cannot be taken into a given area. For example, beer is often a prohibited substance in gaming arenas, meaning that you are not permitted to take it into such areas. The best option among those given is "forbidden," which indicates such banning. Although someone can be condemned for having such a prohibited thing, that is not what is indicated by the word "prohibition" itself. Likewise, a prohibited substance might be "dangerous." This does not mean the same thing as "prohibited" itself.