If you were a scientist studying traits which are selected by humans instead of the environment, you would be studying the following?

The correct answer is: Artificial selection (selective breeding).

Artificial Selection is a form of selection, totally influenced by human, in which traits that should be passed onto offspring are chosen by human. Selective breeding was used long before the genetics was discoverd. Farmers used individuals with beneficial traits, larger in size, with bigger fruit etc.

Hunting is also one type of selective breeding, since the hunters choose the animal and remove it from the population (gene pool), leaving the "weaker" to pass on to the next generation.