Allele frequencies in a gene pool may shift randomly and by chance. what is this random shift called?

a) genetic drift
b) directional selection
c) gene flow

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.

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