Which best describes the exocrine glands?

The answer is C.

or

Exocrine glands secrete substances into the bloodstream.

:D

b. the carbon cycle ensures living things have a source of hydrogen

imagine a line passing through the center of earth that goes through both the north pole and the south pole. this imaginary line is called an axis. earth spins around its axis, just as a top spins around its spindle. this spinning movement is called earth's rotation. at the same time that the earth spins on its axis, it also orbits, or revolves around the sun. this movement is called revolution.