The cow bos primigenius (which is bred for meat and milk) has a smaller brain and larger eyes than closely related wild species of ungulates (ungulates are a group of large mammals that includes cattle, horses, deer and camels). these traits most likely arose by

they arose by artificial selection. this is because to obtain animal with this traits, there is an interference by humans. i.e these organisms do not result from natural selection. the process of obtaining organisms with increased number of desirable traits is referred to as hybrid vigor. in this process an animal with certain desirable trait is bred with another animal with another different type of desirable trait. the resulting offspring will have both desirable traits. 

A) Directly changed by the experimenter  

Explanation:

In mathematical modeling, analytical modeling and experimental sciences, the values of dependent variables depend on the values of independent variables. The dependent variables describe the output or outcome whose change is being examined. An independent variable seldom named an experimental or predictor variable, is a variable that is being formed in an experiment in order to inspect the impact on a dependent variable, sometimes described as an outcome variable.