Answer:
Experiments reveal that human behavior is greatly influenced by humans' desire to fit in.
Her nervousness had a profound effect on her ability to play the piano it effects me too
The sentence does not contain any errors in period usage is letter (A)<span> Have you read The Hobbit by J. R. R. Tolkien? Letter B is lacking a period after 'Lt'. Letter C lacks period after 'Rev' and letter D lacks a period right after the word 'Sgt.' As much as possible, contracted titles should have periods right after it.</span>