Answer:
A, the sun.
Explanation:
The sun powers the water cycle and many others.
<span>Aquatic biomes are characterized by water</span>
Secretion of human chorionic gonadotropin [HCG] only occur during pregnancy in the placenta. The concentration of this hormone increase rapidly during the first three months of pregnancy; the amount in the blood stream doubles every two to three days as the development of the placenta and embryo progress. The hormone reaches its maximum concentration peak around the sixth week of pregnancy and after this, its concentration decline.
<span>Option D correctly describes seafloor spreading. Seafloor spreading is a process which typically occur at middle ocean ridges where new oceanic crusts are formed as a result of volcanic activity. These oceanic crusts then gradually move away from the ridge.</span>
