Which statement is true about nitrogen and oxygen
a. neither contains subatomic particles
b. they are both made of portions, neutrons, and electrons
c. they are both used to make water molecules
d. they make up about 99.9% of the human body

Nephrons, the functional unit of kidneys, are responsible for formation of urine. the sentences describe situations that are the result of problems in the urine formation process. for the nephron shown below, match each situation to the step in the urine formation process where the problem lies.