Here, we have to distinguish between the most important parts of the second sentence and the less important parts. The most important part of the sentence states that the word lithophyte comes from lithos and phyte. The definitions of those Greek words are less important. The definitions can be thought of as asides, so they should be enclosed in parentheses. Though separating out the definitions using commas or dashes might work, a pause is needed between the part of the sentence about lithos and the part about phyte, which is why the other answers do not work.

In this sentence, “cinnamon, nutmeg, and butter” gives extra information about which ingredients were missing; however, this information isn't necessary for understanding the overall meaning of the sentence, so it can be thought of as an aside and enclosed in dashes. Asides have to begin and end with the same type of punctuation, which is why some of the other answers are not right.

This sentence is correct as it is. The part of the sentence enclosed by dashes, “contrary to what many students, adults, and even college professors believe”, gives extra information that can be cut out of the sentence without affecting the sentence's grammar. Asides like these can be enclosed by dashes or parentheses, but they have to be introduced and end with the same kind of punctuation.

Here, the phrase “old chants, laments about separation” is similar to an appositive. It's a phrase that gives more detail about what types of songs the speaker's father sang in the refugee camp. Though this additional information is nice, it isn't necessary to understand the sentence. You could cut out the phrase so that the sentence read, “In the camp we used to sing songs, and we prayed.” So the “old chants, laments about separation” can be understood as an aside, and set apart with dashes. Asides need to open and close with the same type of punctuation, which is why some of the other answer choices would not work.

Here, the first part of the sentence, “Because it was raining,” is a dependent clause; it cannot stand by itself as a complete sentence. The second part of the sentence, “The elementary school students had recess inside the classroom” is an independent clause; it can stand by itself as a sentence. Connecting these two types of clauses just requires a comma, not any type of fancier punctuation like a dash or a colon.

Here, we can break up the second sentence into two independent clauses, “Instead, she preferred 'Rebecca'” and “she said that name made her feel more like her own person." Both of these can be sentences in their own right. Two independent clauses can be joined by a comma followed by a conjunction, a dash, a semicolon, or, in certain cases, a colon. The only one of these pieces of punctuation offered as a possible answer is the dash, so that is the right answer.

In the underlined part of the sentence, the phrase “by then, it was already getting dark” gives extra descriptive information; however, we don't really need this extra information to understand the sentence as a whole. So, we can punctuate it as an aside, by enclosing it within dashes or parentheses. Asides have to begin and end with the same type of punctuation, so the only right answer is the one that surrounds “by then, it was already getting dark” with two dashes.

Here, the first part of the sentence, “Despite the car salesman's assurances that the used car had been inspected and showed no problems,” is a dependent clause. It cannot stand by itself as a complete sentence. The second part of the sentence, “my brother still had reservations about its safety,” is an independent clause, or a clause that can be a complete sentence by itself. To connect these two types of clauses here, we only need a comma.

Grammatically, the first sentence is fine as it is; however, the second sentence, as it is written, is a fragment. When we combine these two sentences together, we have to think about what is the most important information, and what is additional, unnecessary information. Here, you could cut out the phrase “clothes, friends, neighborhoods, ideas”, and instead write “we leave behind certain things that defined us in the past, and leaving behind these things allows us to grow and change.” We can think of the phrase we could cut out as an aside, and enclose it between two dashes. We have to introduce and close an aside using the same sort of punctuation, which is why some of the other answer choices don't work.

As it is written, the last sentence here is a fragment, so it needs to be corrected. We should connect the second and third sentences together. But how?

The phrase “Flavors that I had never imagined” continues the idea from the second sentence about how the shop had so many flavors of ice cream; however, “Flavors I had never imagined” provides extra information that isn't really necessary to understanding the sentence. We could cut that phrase out, and write, “There were so many flavors of ice cream on the menu, and it took me.” The best way to understand “Flavors I had never imagined” is to think of it as an aside, which should be enclosed in either parentheses or dashes.