A) causes an effector to signal the control center of an organism, which creates the stimulus to make a response
Answer:
D
Explanation:
Most of the energy in the United States comes from the burning of fossil fuels (coal, oil, natural gas). Hope this helps!
The right side of the heart sends blood out to the lungs to become oxygenated and that oxygen-rich blood comes back to the heart on the left side. Then the left side of the heart pumps the oxygenated blood to the rest of the body.
