Answer:
Suface currents are mostly caused by the wind because it creates friction as it moves over the water. This friction then forces the water to move in a spiral pattern, creating gyres. In the northern hemisphere, gyres move clockwise; while in the southern hemisphere, they spin counterclockwise.
I don't really get your question sorry :(
Nephrons. These are a particle in the blood.
I am pretty sure it is Sexual selection.
