Very confusing GRE Reading Comprehension passage. My way of reasoning is mentioned. Please help with mistake in my way of reasoning

Question

In own words: The rapid gravitational collapse theory was challenged by the observation during the studies of moon craters. The study revealed that the craters were caused by impact of objects(probably planetesimals) that were in abundance 4.5 billion years ago but whose numbers decreased therafter. However, this observation was supported by Schmidt's theory of accretion: Cosmic dust gradually lumped into larger conglomerates and ultimately,planets. Consequently, the number of collisions between planetesimals decreased as their sizes became larger and their numbers decreased.

Q24:

A: The words rapid and gradually confirms that the time taken for planet formation contradicted in the two theories. A is correct. Fine.

B: The first theory cannot prove the Cause of Moon's impact craters since everything happened so suddenly. "That view was challenged" in line 3 confirms this. But Schmidt's theory was "rejuvenated" by this observation: suggests that the two theories contradict in explaining likely causes of impact craters. Therefore option B must be coorect according to my reasoning but its not.How?? The explanation given in the GRE textbook is vague and incomplete.

C: Fine.Schmidt would agree as the first theory also has dust cloud or cosmic dust as the seminal material. C isnt correct.

Q25:

D is the answer.

Answer 1

Neither of the two theories questions or even involves the cause of the craters in question, viz. the impact of planetesimals. The key factor in the 1960s observations, and what called the old theory into question, was not the fact of the craters but their timing—which was not known to either Schmidt or his opponents at the time their theories were advanced.

Answer 2

StoneyB explained why Q24 (B) is not correct. I'll deal with Q25.

The 'observation' is this:

These craters were caused by the impact of objects that were in great abundance about 4.5 billion years ago but whose number appeared to have quickly decreased shortly thereafter.

Incorrect answers

(A): The observation in and of itself says nothing about how the rocky planets were created. It only talks about how the change in abundance of objects whose impact created the craters, namely that this abundance was high 4.5 billion years ago and then quickly went down. There is not a word about planet creation in that.

(B): Yes, this aspect is a prerequisite of the observation, but that's the part that everyone knew even before it. The observation is about how 4.5 billion years ago there was a quick decrease in the abundance of the objects whose impact created the craters

(C): This is wrong for the same reason (A) is wrong. True, this is what people were able to infer from the observation, but that wasn't the content of the observation itself.

(E): This is consistent with the observation, but it would also be consistent with e.g. a steady decrease in the number of planetesimals over the eons. But what the observation says is that the decrease wasn't steady: it happened quite rapidly about 4.5 billion years ago. And this rapid nature of the decrease is the whole point.

The correct answer:

(D): This is just the paraphrase of the observation, except that it omits the exact time when the rapid decrease occured.

Answer 3

The questions seem to revolve around what was known when and what is a direct observation in contrast to what is later deduced by comparing theories. Here's my take. (I highlight the parts which I think most directly answers your questions.)

For 24, the correct answer is the one Schmidt would disagree with.
24
A) Like you say, Schmidt would disagree on the length of time it took for planets to form. Other scientist believed in rapid gravitational collapse, while his theory speaks of a gradual accretion of planetary material. So this answer is correct.

B) There is no evidence in the passage to suggest that Schmidt had any theories on the moon craters or whether or not he knew about them. So this answer is incorrect.

C) Cosmic dust is a central factor in Schmidt's accretion theory so he would not disagree with its importance. So this answer is also incorrect

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For question 25 I find it helpful to rewrite the exact observation:
Studies of the moon craters revealed that these craters were caused by the impact of objects that were in great abundance 4.5 million years ago but whose numbers appeared to have quickly decreased shortly thereafter.

A) Incorrect. This is clearly not the observation
B) This is not the precise observation either, because it was only later that Schmidt's theory was rejuvenated and the objects could be described as planetesimals. Incorrect
C) Incorrect. Clearly not the observation.
D) Correct. It corresponds to observation.
E) Incorrect. Again, the observation about the moon doesn't say anything directly about planetesimals (although it could be deduced when comparing to Schmidt's revived theory.)