Answer: option (D).
Explanation: Nicholas fiddled with his thumbs, because, he didn’t dare look at his sister as she towered over him.
Commas are mostly used to divide or separate parts of a sentence in order to make the meaning clear and the sentence easier to read. Commas mark a brief pause in the sentence, usually at a point where you would naturally pause if you were speaking rather than writing.
Answer:
some comet are very difficult to see because they are made of water and dust and they reflect light very well, so scientists only know about those that make regular appearances, and some comets have not been discovered yet and due to that scientist both sky watchers and strong telescope to report new comets and only them can identify them, although some comet can be seen easily by ordinary people
Explanation:
Although some comet are difficult to see, scientist uses sky watchers to help them to spot them, they also use strong telescope to identify them
I think it is sentence D. Hope this helped<span />