Because it needs to be able to be proven and it avoids being incorrect.
Answer:
D
Explanation:
A geometric progression is multiplication by a number. In this case, it is 3.
If you take 4, multiply it by 3, you get 12. Multiply 12 by 3, you get 36. And so on.
It means to make something productive. "the action or process of fertilizing an egg, female animal, or plant, involving the fusion of male and female gametes to form a zygote."
By elimination: d is wrong for sure.
c is not right as there is no gland in the esophagus or the pharynx
b is also wrong as if there is no gland, then there is no enzyme and no chemical digestion in <span>esophagus or pharynx
a is the only one left.</span>
