B - Because an active cell can only work if it has a 3-Dimension structure.
Correct answer: A) Extension
Extension is a physical position that occurs when angle between the bones and the limbs of joint increases.
It takes place when there is a contraction of muscles and bones move the joint from a bent to a straight position, it is opposite of flexion, in which the angle between the bones and the limb at the joint decreases.
Example: During straightening of the leg, the angle between the tibia and femur increases, which shows extension has taken place.
I'm pretty sire the answer to this would be
c. <span>add new genes to the gene pool </span>