Answer:
A. Volcanic ash falls to the ground and adds minerals to the soil,
making it rich for plant growth.
The correct answer is - D) covered by warm shallow seas.
The fact that the crinoids are have an abundance in the fossil records in Pennsylvania in the Mississippian Period, tells us that this area was covered with shallow and warm seas. The reason why we can get that conclusion is that the crinoids live only in that kind of environment, so it simply a logical conclusion.
The geological data is also confirming this, as it is easily noticeable in the layers that during this period of the geologic past, what is now Pennsylvania, was covered with shallow sea waters. Also, this waters were warm too, as the climate was warm and humid and that period, so it was a perfect environment for the crinoids to flourish.
It is a rare genetic mutation that both the maternal and paternal partners have to be at least a carrier for the albinism gene.
500 million for the first picture and for the text i guess it evolved physical reproductive body cells and parts that makes sexual reproduction change as itself as well as birth due to not only human nature but man made things as well, example: hospitals, medicine, chemicals, etc.
