Your question is missing the options. I've found them online, they are as follows:
Which sentence best identifies the main idea of paragraph two?
a. Scientists are baffled by the different ways the rocks move.
b. Scientists are confused by the different ways the rocks move, and theories involving wind, ice, and mud have not been confirmed.
c. Scientists have theories of how the rocks move.
d. The rocks have stumped scientists because some roll, some take unexplainable routes, and some have traveled past ones that have stayed still, but scientists have theories that the rocks are pushed by wind or that they slide on ice or mud.
Answer:
The sentence that best identifies the main idea of paragraph two is:
b. Scientists are confused by the different ways the rocks move, and theories involving wind, ice, and mud have not been confirmed.
Explanation:
Sentences A and C are incomplete on their own. Paragraph two discusses both of them, not just one or the other. Sentence D, on the other hand, does not express the main idea. It actually offers details and is, by itself, a paragraph. Sentence B is the best option since it expresses, in a succinct way, what paragraph two discusses: how scientists are confused and what theories they have come up with.
