The correct answer is B.
The first two sentences are establishing characteristic shared by both petroleum and coal. The word "however" is used to contrast the similarities already presented with the differences that will be stated in the following sentences.
Answer: D) They had not seen the experiment, yet they knew the results.
Explanation: a conjunction is a an uninflected linguistic form used to connect clauses, phrases, words or sentences or to coordinate words in the same clause, for example: and, if, so, yet, but, or, nor, etc. In the given sentence we can see an example of a conjunction in the word "yet" it is joining two independent clauses: "they had not seen the experiment" and "they knew the results."
Answer:
1. Seals sit on rocks in warmer are by the oceans. 2. Scientists can collect data about currents.
3. We tend to wear hats in sunny climate and in warm temperatures.
Explanation:
They would probably think of thunder for a birds wings flapping.