Which body system assists the respiratory system in the exchange of chemicals within the body's cells? O A. circulatory
B. reproductive
O C. excretory
D. digestive

Building glycogen from glucose molecules is an example of what

The nervous system interacts with the endocrine system by a. using hormones as connections b. sending nerve impulses directly to glands c. using neuroendocrine cells as connections d. sending neurotransmitters directly to neurons

Which of the following is a testable hypotheses?