Answer:
B(sperm production)
D(appearance of secondary sex characteristics)
Explanation:
All of those can potentially harm the earth. Human activity is a cause of pollution, and pollution is the cause of acid rain to some extent.
The answer is C. Maybe im not sure
Answer:
if sex cells were identical, there won't be genetics variations and we will just all be identical to our parents. genetic variation allows us to better adapt and survive
