<span>During JURASSIC period the first true mammals appear.</span>
B THEY RELEASED CARBON DIOXIDE, WHICH EVOLVING ANIMALS NEEDED.
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 !
Answer:Primary succession occurs on land that is new and has never had a flora and fauna example: glacier retreats, lava flows. Secondary succession occurs on land that has been cleared example: by fire, of flora and fauna, but which still has viable seeds and spores in the soil.