This is some barrier to reproduction among a species of organisms. it often results in genetic change over time and the development of new species.

What type of cell is produced after fertilization occurs and the gametes combines ?

What are some characteristics of a free enterprise economy?

When new rock is added to an oceanic ridge, the magnetized strips on either side of the ridge are evidence of sea-floor spreading. this is because the rocks on the two sides of the ridge o are equal in width and in polarity are polar opposites oare magnetized vary in width but are equal in polarity