Elisa feels tired because she has a condition that affects whether the right molecules are getting to her cells. If her body were functioning correctly, this is what would happen with oxygen:

How are the cell walls of a plant and fungus different ?

What is a universal way that predation benefits the predator? predation increases mate availability. predation in defense of space. the predator gets the energy it needs to survive. the predator keeps parasites from hurting the species.

Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins