Answer:
Artificial selection
Step-by-step explanation:
The process is an example of artificial selection.
Artificial selection is process in which members of a population with desired features/characteristics are deliberately favored to reproduce within the population.
The process which is also referred to as selective breeding is used by man to selectively develop particular phenotypic traits in farm animals.
In this case, the desired traits are increased milk production and larger muscle size and these two traits co-occurred with having smaller brain and larger eyes. Hence, the latter traits are selected for in order to get the desired traits.