Why Do Cells Need to Communicate

Why do cells need to communicate?

A) Otherwise, they keep dividing and pile up and lose contact with each other such that they can't do the job in the body that they should.
B) Otherwise they die.
C) If they can't communicate, they don't divide, so they age and deteriorate
D) They don't need to because the brain controls the body functions.
E) Otherwise, they stop dividing and they can't do the job in the body that they should.