I can't see the well but chemical changes happen when a substance combines with another to form a new substance. These processes are called chemical reactions and are not reversible except if you do more chemical reactions... So the well that is changing it's state of matter should be the one undergoing a chemical change. For, example boiling or freezing
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:
B. CO2 out
Explanation:
The excretion is the process of removal of the waste product from the body. The carbon dioxide is the byproduct of the aerobic respiration, which is carries from the tissues and the lungs by blood. In the lungs at alveoli, the carbon dioxide is transferred from the blood to the lungs and released out through the nostrils. Hence, the out of the carbon dioxide represent excretion through lungs.
Nucleotides. They are the building blocks of DNA.
