The first sentence tells us maples "thrive in a wide variety of climates." The second sentence talks about "alterations" they undergo. This strongly suggests that maples are good at *changing* to fit their environment. So, before even looking at the choices, we're thinking of a word like "change" or "adjust."

Now, let's look at the options:

• (A) relocate: This means to move to a new place, not to change internally.
• (B) refer to: This means to mention or allude to something. Doesn't fit.
• (C) originate: This means to start or create. Also doesn't fit.
• (D) adapt to: This means to adjust to new conditions. Bingo! This is exactly what we predicted.

The key phrase is "so clear that it was almost invisible." This means you could see right through the water to the bottom. We're looking for a word that describes that level of clarity.

(A) simple: This means uncomplicated, not necessarily clear.

(B) understandable: This refers to being easy to comprehend, not visual clarity.

(C) obvious: This means easily seen or understood, but doesn't capture the "invisible" aspect.

(D) transparent: This means allowing light to pass through so that objects behind can be distinctly seen. Perfect!

We have a contrast here. The observed burst lasted 200 seconds, but *typical* bursts last fewer than 2 seconds. That makes the 200-second burst something unusual or unexpected.

(A) coincidence: This implies a chance occurrence, but the text suggests a significant difference.

(B) reprieve: This means a cancellation or postponement of punishment. Doesn't fit.

(C) incident: This is a general term for an event, too broad for this context.

(D) oddity: This means something strange or unusual. This is the best fit.

The sentence directly links Franklin's "popularity" to his success in convincing France. We need a word that's closely related to popularity or the positive regard in which he was held.

(A) thoughtfulness: This means being considerate of others, not the same as popularity.

(B) esteem: This means respect and admiration. This is a strong contender.

(C) trouble: This is the opposite of what we're looking for.

(D) sincerity: This means being genuine, but doesn't necessarily imply popularity.