Which statement describes two organ systems working together to make an animal run away from danger?
A. The heart beats faster when the nervous system senses a high
level of carbon dioxide in the blood.
B. The nervous system sends signals that cause the adrenal glands
to release hormones.
C. The immune system produces antibodies when white blood cells
detect pathogens.
D. The endocrine system releases hormones that cause bones in the
arms and legs to grow longer.