Answer: the body plans of complex animals are very similar to one another
Scientists believe that great apes such as chimpanzees and gorillas are more closely related to humans based on the evolutionary timeline because apes are larger than monkeys and have long legs and no tails. Apes are known to have larger brains than monkeys which makes them so closely related to us. This fact cancels out B and C for the answer. Also, apes (gorillas, orangutans, etc.) are much larger than monkeys (mandrill, lesula, etc.). This right away cancels out option D. What's left is option A which features body parts and comparisons that are comparatively accurate towards humans. Hope this helped :))
Lining the thoracic cavity
The correct answer is C - it is only seen in homosexuals who have intimate sexual contact with homosexuals
Explanation - anyone and everyone can get aids