Question

testosterone directly affects the
production of sperm
cells

development of a
placenta

formation of a zygote

changes within an
ovary

Explanation:

Testosterone is the primary male sex hormone. The production of sperm cells is a key function related to male reproductive physiology, and testosterone directly stimulates the production of sperm cells (spermatogenesis) in the testes. The development of a placenta is related to female pregnancy (estrogen/progesterone - related), formation of a zygote is fertilization (not directly affected by testosterone), and changes within an ovary are female - related (ovarian cycles, estrogen - driven). So the correct option is the one about production of sperm cells.

Answer:

A. production of sperm cells (assuming the first option is labeled A, with the text "production of sperm cells")