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.
A scientist who studies living things is called a biologist
Answer:
Through photosynthesis, organisms could use sunlight to make food from carbon dioxide and water.
They provided food for themselves
Explanation:
Unlike freshwater fish, saltwater fish <span>often contain a lower concentration of salt than the water they live in.
so your answer is </span><span>A. often contain a lower concentration of salt than the water they live in.
hope that helps!!!!!</span>
