The second sentence, because "sometimes anything" goes with the verb form "beats". "Sometimes anything beats" is more correct than "sometimes anything beat"
B. must be related.
The main point of having a thesis statement is to explain the certain topic. Topic Sentences are sentences that explain how the topic is related to your thesis statement so it must always be relevant.
Active voice is a sentence form wherein the action, represented by the verb, is done by the subject. Therefore, the sentence that is written in the active voice is, option B. Scientists found a perfectly preserved woolly mammoth frozen in ice. The subject in the sentence is the word "scientists" and the action word "found" is done by the subject.