Cholesterol and steroid synthesis occurs in the:

This structure propels fluids/mucus:

The kidneys are part of which organ system? (You may need to select more than one answer)

A fully-assembled protein composed of 2 or more polypeptides constitutes:

_____ glands have ducts.

Amino acids differ only in their:  

__________ fibers have the highest tensile strength. 

Attraction between two polar molecules constitutes:

Which level of organization is the smallest (or lowest)?

The outer layer of the nuclear envelope is continuous with the rough ER.