Which of the following nutrient cycles has its largest reservoir in the atmosphere?
a) carbon cycle
b) nitrogen cycle
c) potassium cycle
d) phosphorus cycle
e) water cycle

Match the description of each organism to the appropriate category

Amino acids contain the elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. of the 20 amino acids found in humans, 11 are called "nonessential" because they can be manufactured by the body when needed. which elements in these 11 amino acids are commonly obtained from the metabolism of sugar molecules?

Blood stem cells may develop into any kind of human blood cells. what kind of stem cells are blood stem cells? a. multipotent stem cells o b. totipotent stem cells o c. pluripotent stem cells o d. unipotent stem cells