Blood calcium concentration is maintained relatively constant even when calcium intake increases. based on this information, one can conclude that:
a. blood calcium must be needed for the normal function of many cells.
b. the blood calcium concentration must be controlled by the nervous system.
c. there must be a mechanism to detect the concentration of calcium in the blood.

b

explanation:

the denominator has a very specific role.

1. the energy lost to disorder metabolism     -entropy

2. related to or possessing motion potential     -kinetic

3. all of the chemical reactions in an organism required for maintenance of the processes of life entropy     -metabolism

4. possible; ability to go into action or perform work kinetic     -potential

5. the study of energy and its transformations thermodynamics     -thermodynamics