The process that results in the formation of different cell types occurring through selective changes in genetic activity that causes some genes to be turned off, while others are turned on is called

Differentiation

Explanation:

 The differentiation is one of the type of normal process that occur due to the selective change and it is distinct from in the function. The differentiation is basically refers to the breaking into the smaller parts.

According to the question, the formation of the different types of cell which cause the genes sometime ON or OFF then this process is basically known as the cell differentiation. This process is mainly occur due to the process of genes expression.

Therefore, Differentiation is the correct answer.  

thots think tootsies drink tequila

answer; all of the answers are correct;