The answer is to your question my friend is D.
Answer:
Tributary-river-river system
i think this is the answer
Explanation:
According to G.D Budhiraja in his book "The Natural Way of Healthy Aging," the ultimate wonder of cells is the egg cell.
The egg cells is considered to be the ultimate wonder of cells because of its potential to form another human being. Once fertilized, the egg cell multiplies and grows, and "seems to know" just the right timing for certain processes to occur within the embryo or fetus. It seems to know when certain hormones should be produced, when it should implant in the uterus, and when the hands, legs, feet, hair, and other parts of the embryo and fetus should grow.
