Answer:
Ventlation or breathing, is the movement of air through the conducting passage between the atmosphere and the the lungs. The air moves through passeng because of pressure gradients that are produced by contraction of the diaphragm and thoracic muscles.
Pavlov's dog stopped salivating to the bell when the food was no longer paired with the bell. This is called:
extinction
Blood cells are produced in the bone marrow and the bone marrow is part of the skeletal system. So the answer would be skeletal system<em>. </em>
The answer to 2-7 would be -5, but 7-2 would be 5, depends how specific one is trying to be.
