What’s the role of oxygen in cellular respiration?

A.
It accepts electrons and keeps the electron transport chain running.
B.
It breaks down carbon-based sugar molecules to release energy and forms carbon dioxide.
C.
It combines with hydrogen ions in sugar molecules to release energy and form water.
D.
It supplies electrons to the electron transport chain to keep it running.

What sentence best supports the statement that hormones are involved in the regulation of homeostasis? a. the hormone erythropoeitin increases the production of red blood cells when oxygen levels are low. b. the hormone oxytocin promotes labor contractions of the uterus during childbirth. c. the hormone melatonin induces sleep and its production is slowed by exposure to light. d. the hormone cortisol suppresses the immune system and is produced when the body is under stress.

Migration is a. the movement of organisms from a native location to a foreign location b. the movement of organisms from a foreign location to a native location the movement of organisms from their water supply to their food supply d. the seasonal movement of organisms between locations c. select the best answer from above

How water is moving through the ecosystem ?