The cramping associated with premenstrual syndromeis often due to norepinephrine.

If fertilization occurs, the progesterone levels fall to almost zero.

The main function of carbohydrates is for long-term energy storage.

What does the word   trophic mean?

The reabsorption of water in the kidneys always precedes the reabsorption of salt.

Why is the dialysate continually replaced in hemodialysis?

Lymph capillaries drain directly into the right lymphatic duct.

How is the nitrogen cycle like the carbon cycle?

The white matter of the spinal cord surrounds the gray matter.

An important part of scientific research is repeatability.