A brain cell and a kidney cell have incredibly different structures and functions, yet they both have the same exact sets of genetic information (DNA) in their nuclei. Which of the following answer choices best explains what process lead to each cells' unique structures and functions?
Choose 1
Choose 1

(Choice A)
A
During fertilization, a sperm cell fused with an egg cell, resulting in a zygote.

(Choice B)
B
Differentiation allowed the brain and kidney cells to become specialized for the structures and functions they possess.

(Choice C)
C
A series of specific mutations allowed the brain and kidney cells to become specialized for the structures and functions they possess.

(Choice D)
D
Apoptosis allowed the brain and kidney cells to become specialized for the structures and functions they possess.