Answer:
A - Doing research on how plastic effects the enviorment
Step-by-step explanation:
Biology is the field of science that is all about living things, and the proccess of the natural world.
The mechanics of ships is man made, and not livng or apart of the natural world
Plastic bag construction is also man made.
However, the enviroment is a part of the natural world, and how plastic bags effect it could be considered biology.
So your answer is A.