Answer:
Strong selection for change is acting on this gene.
Explanation:
The first trimester is when the embryo attaches to the placenta by the umbilical cord and the placenta make contact with the uterus.
(the answer is b)it coulve been a but it say "only" and stress has a lot of effects on the body and c and d are answers to trick you but you have to pay attention to what it actually states
I believe it is c but not quite sure
