Answer:
Calcium has an Atomic number of 20 and Atomic mass of 40.078 u
Hope this helps!
Answer:
Exchange across cell membranes - diffusion. The higher the concentration gradient, the faster the rate of facilitated diffusion, up to a point. As equilibrium is reached the concentration gradient is much lower because the difference in concentrations is very small so the rate of facilitated diffusion will slow down and level off.
Explanation:
They are arranged in shells
I believe the medulla is the answer.