A skeleton is comprised of bones, so we need to pick out an answer choice in which the first word is made up of the thing the second word refers to. While "thread is to cloth" might look like a good answer choice because cloth is made up of thread, it can't be the correct answer because the two words are in the incorrect order—skeletons are made of bones, but thread is not made of cloth. Log cabins are made up of logs, however, so "log cabin is to logs" is the correct answer.

Since a snowflake is a single unit of snow, and a snowdrift is composed of a lot of snowflakes, we need to pick out a word that describes something that is composed of a lot of water drops. Since "downpour" is the only answer choice that is made up of lots of raindrops, "downpour" is the correct answer.

"Tornado" is a noun that means "a mobile, destructive vortex of violently rotating winds having the appearance of a funnel-shaped cloud and advancing beneath a large storm system." So, because a tornado is a natural disaster that consists of wind, we need to pick out an answer choice in which the second word represents a natural disaster caused by or composed of the first word. "Rain is to rainbow" might look like a potentially correct answer, but since a "rainbow" is not a natural disaster, it cannot be the correct answer. However, because a snowstorm is a natural disaster created by snow, just like a tornado is a natural disaster created by wind, "snow is to snowstorm" is the correct answer.

Since snow is what a snowman is made of, we need to pick a word that describes something that is made of ice. Because icicles are made of ice, "icicle" is the correct answer.

A beach is made up of sand. That means we're looking for something that makes up a river. While "stones" and "fish" can be found in a river, they aren't what form the river. A "lake" and "ocean" are other types of water. "Water" is the only answer that fits.

A "candle" is usually made of "wax." So, to solve this analogy you need to determine which of these answer choices is often made from "cotton" (a type of fabric, a type of material used to make clothes). The correct answer is "sweater."

"Jam" is usually made from "fruit," so to solve this analogy you need to figure out which of these answer choices "cheese" is usually made from. The correct answer is that "milk" is used to make "cheese."

A "galaxy" is the name given to a collection of "stars." Our galaxy is called "the Milky Way." To solve this analogy you need to determine which of these is a name given to a collection of "books." The correct answer is a "library." 

An "omelet" is made using "eggs." So, which of these is something that is made using "flour?" The correct answer is a "cake."

Sweaters are often made of wool. Therefore, we must look for the answer that shows a relationship between a product and the material from which it is made. Shoes are often made of leather, so the correct answer is "shoe is to leather."