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.
Answer:
I'm pretty sure the answer is B! Hope this helps:]
Answer:
precession
Explanation:
The orbit isn’t the simple ellipse, rather it is one that moves a little, loop after loop. This motion is called precession, and you may have heard about it when astronomers talk about the precession of the orbit of Mercury
