When a word contains the root “aqua,” it usually refers to something having to do with water, so you can tell that “aquatic” means living in or near water. Whales live in water. So, to solve this analogy, you need to pick out an adjective that describes where sloths live. Sloths spend most of their time in trees, so you need to find a word that means something like "living in or near trees." “Arboreal” means living in or near trees, which makes sense, as "arboreal" is derived from the Latin root "arbor," which means tree. “Amphibious” describes an animal that lives both in water and on land, whereas “terrestrial” refers to animals which only live on land. To help further, “grounded” can mean stuck on land or in one place whilst “mountainous” describes land or terrain that contains mountains.

A rabbit could be the prey of a hawk, meaning that a hawk might eat a rabbit, so we need to pick out an answer choice that describes an animal that might be the prey of a frog, or is something that a frog might eat. While “dragonfly” and “heron” might each look like a potentially correct answer, “heron” cannot be the correct answer because a heron might eat a frog, but a frog would be very unlikely to eat a heron. A frog might eat a dragonfly, though, just as a hawk might eat a mouse, so “dragonfly” is the correct answer.

"Pig" is the name given to an animal, and "pork" the name given to the meat that animal provides. So, we need to pick out a word that is used to describe the meat a cow provides. While "beef," "calf," and "steer" all have to do with cows (a "calf" is a young cow and a "steer" a term for a male cow), "beef" is the correct answer, as meat from a cow is called "beef" just as meat from a pig is called "pork."

“Ewe” is a noun that means a female sheep, while “ram” is a word that when used as a noun can mean a male sheep. So, because “hen” is a noun that can mean a female chicken, we need to pick out an answer choice that means a male chicken. Both “rooster” and “bird” might look like potentially correct answers, but “bird” specifies a general category into which "hen" could fit, along with other types of birds besides chickens, and it could also refer to an organism of either sex, so it cannot be the correct answer because we’re specifically looking for a word that means a male chicken. “Rooster,” however, is a noun that means a male chicken, and because “rooster” is the name given to a male chicken while “hen” is the name given to a female chicken, just like “ram” is the name given to a male sheep and “ewe” the name given to a female sheep, “rooster” is the correct answer.

"Armada" is a noun that means "a large group of ships or boats," so we need to pick out a word that describes what, in a large group, constitutes a flock. "Seagulls," "wolves," and "dinosaurs" might all seem like potential answers because they are all animals, but since "flock" means "a number of birds of one kind feeding, resting, or traveling together," "seagulls" is the correct answer, since seagulls are a type of bird. 

A group of lions is called a “pride,” so to solve the analogy, we need to pick out an answer choice that is a term used to describe a group of geese. A group of geese is called a “gaggle,” so "gaggle" is the correct answer. 

A “leash” is a length of rope, leather, or chain attached to a dog's collar used to restrain and guide it. "Reins” are a leather straps attached to a horse's bridle used to restrain and guide it. So, just as a leash is used to restrain and guide a dog, reins are used to restrain and guide a horse, so "reins" is the correct answer.

A group of ships is called a "fleet," so we need to pick out an answer choice in which the second word is a noun describing a group of the first word’s noun. While both “herd is to deer” and “fish is to school” might look like potentially correct answers, “herd is to deer” cannot be the correct answer because a “deer” is not what one calls a group of "herds," but the other way around. A school is what one calls a group of fish, however, just like how a fleet is what one calls a group of ships, so “fish is to school” is the correct answer.

A shark uses its teeth to bite things, so we need to pick out an answer that describes what part of a snake it uses to bite things. While “fangs” and “scales” might each look like a potentially correct answer because each refers to a part of a snake’s body, a snake uses its fangs, not its scales, to bite things. Because a snake uses its fangs to bite things just as a shark uses its teeth to bite things, “fangs” is the correct answer.

A group of wolves is called a "pack." Similarly, a group of "bison" is called "a herd."

None of the other analogies have this relationship:

"Herd is to fish": herd is not a word used to describe groups of fish.

"Forest is to bush": while there are often numerous bushes in a forest, a collection of bushes is not called a forest.

"Swarm is to fox": Swarm is a word meaning a large group of flying insects, thus foxes cannot form swarms, and a collection of foxes is called a troop or a lead.

"Children is to school": While groups of children are typically found in schools, a group of children is not called a school.