During replication the 2 strands of the dna molecule are unwound from one another by enzymes called

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.

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.