When a man has an erection does he releases sperm

Not necessarily.

Explanation:

An erection is caused by blood flow to the penis. A man can get an erection just by seeing a woman or hearing language that turns him on or excites him. A young man who is not experienced in controlling an erection may release sperm in a spontaneous ejaculation but more experienced men would not likely ejaculate without more stimulation, such as masturbation.

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.