All organisms do have a closed circulatory system
so A <span />
Answer:
<em>change</em><em> </em><em>in</em><em> </em><em>genetic</em><em> </em><em>structure</em><em> </em><em>of</em><em> </em><em>a</em><em> </em><em>popu</em><em>lation</em><em> </em><em>over</em><em> </em><em>time</em>
As epithelial makes the outer covering of all the organs and skin is also made of epithelial...so to be sure that it does not get depleted or destroyed due to friction and other external cause ...it should be highly generative !
