Well here's an image of the things that do occur (different phases). You can see which ones are are right in the answer choices and pick out the wrong one. I hope this helps...
Answer:
cardiac
Explanation:
An electrical stimulus is generated by the sinus node (also called the sinoatrial node, or SA node). This is a small mass of specialized tissue located in the right upper chamber (atria) of the heart. The sinus node generates an electrical stimulus regularly, 60 to 100 times per minute under normal conditions.
Answer: Atmosphere and Continental Crust
Answer: Food
Explanation: Of course, animals need food in order to gain mass. The food is used to transfer into cells, forming tissues, skin, and muscle to the animal.
Hope this helped!
Answer:
Natural selection, the keystone of evolution, can switch direction in a matter of months, a novel experiment on lizards reveals.