Answer:
The Y chromosome is an accurate indicator of a person's external sex organs.
Explanation:
Since females have two X chromosomes while males have one X and one Y chromosome, if you are aware of the presence of a Y chromosome you can safely assume that a person is a male. Therefore, you can assume what external sex organs a male has.
Answer:
C
Explanation:
It is more probable that the third one has a more developed sense of the vision with a large eye, and its movements. Also with a opened back to receive its nutrition and optic nerve.
Sources:
Zihlman, Adrienne. (2006). «The Ape in the Tree». International Journal of Primatology (en inglés) 27 (4): 1227-1228