A district is a part of a given city. For instance, a city might have a “market district” in which a number of food salespeople have shops for selling bulk quantities to potential restaurants in town. There might be an “Italian district” in which a number of Italians live and have set up shops and restaurants, giving the area a distinctive Italian appearance and character. The analogy could thus be rewritten, “As a district is part of a city, so too is an hour part of X.” An hour is part of a day. While it is a period of time, a measure of time, a moment (in the grand scheme, at least), and even “a portion” (of a longer time), it is only part of a day. The analogy requires a part-whole relationship.

Since a yolk is part of an egg, we need to pick out an answer choice in which the first word describes a part of the second word. Either "page is to book" or "finger is to hand" could be the correct answer. Since a yolk is contained within an egg and a page is contained within a book, but a finger is not contained within a hand, "page is to book" is the better answer of the two choices and the correct answer.

An atom is the basic part from which molecules are constructed; therefore, this is a part-whole analogy. A minute is part of a larger measure of time. Here, you have to be careful. Two options are justifiably tempting, namely “hour” and “century.” Now, “molecules” are the “first rung” of combined atoms. We could, of course, say that organs are made up of atoms; however, this could be stated as “organs are made up of tissues, which are made up of cells, which are made up of molecules, which are made up of atoms.” Notice that “molecule” is the immediate product of atoms, not a distant one (as in the case of organs in relation to elements). This means that “hour” is a better option than “century.”

Since kernels are the edible seeds of corn, we need to pick out another set of words in which the second word describes the edible seeds of the plant the first word represents. While many of the answers have to do with vegetables, "sunflower is to sunflower seed" is the best answer, because sunflower seeds are the edible seeds of sunflowers. 

This analogy is relatively simple. A pocket is part of a shirt, so you are looking for the that of which a lace is part. While lace can be a type of plaited fabric, here, the best option is to understand it as meaning the long string used in things like shoes. The lace is part of a shoe as a pocket is part of a shirt. 

A "link" is one of the small metal pieces in a longer chain. It also can mean any portion of a long “chain” of things (understood metaphorically). Hence, we speak of the “missing link” between apes and men—that is, the missing intermediary stage / being in the great chain of beings. The analogy could be written, “As a link is part of a chain, so is a chapter a part of X.” “Book” is the only option of something of which a chapter is a portion. (A chapter, of course, could be a part of a thesis, a novel, a report, etc.).

A citizen is a member of a nation and could justly be called a part thereof. Our bridge sentence could thus be written, “As a citizen is a part of a nation, so is a branch a part of a X.” Among the options provided, only “tree” gives the larger thing of which a branch is a part.

The hinge is the part of the door that lets it swing. Similarly, the fulcrum is the part of the lever that lets the lever arm swing.

“Dregs” are defined as either “the remnants of a liquid left in a container; sediment, grounds” or “the most worthless parts of something.” So, the bits left in the bottom of a glass after one drinks tea are called “dregs,” and we need to pick out an answer choice that is a noun conveying what might be left in the bottom of a glass after drinking coffee. While “grounds” and “beans” are both words associated with coffee, coffee is made from beans, but one does not find “beans” in the bottom of one’s empty coffee mug, so “beans” cannot be the correct answer. “Grounds,” however, is a noun that can mean “solid particles, especially of ground coffee, that form a residue; sediment.” So, because tea might leave dregs in the bottom of a glass while coffee might leave grounds in the bottom of a glass, “grounds” is the correct answer.

The outer "framework" of an animal's body is its skin, which protects its insides. A similar relationship exists between an orange and its peel, since the peel is the outer part of the fruit which protects the inside.