Which of the following could be said about ecological footprints?
a. ecological footprints can't be used to determine carrying capacity.
b. ecological footprints don't take into account resources needed to absorb and manage wastes.
c. exact ecological footprints are often difficult to calculate, but estimates can be useful in comparing populations.
d. the average ecological footprints for various countries are nearly identical.

After frida stops exercising, she continues to breathe heavily. what is most likely occurring in her body? heavy breathing during exercise has produced an oxygen surplus in her muscles. this oxygen is being transported to her lungs. this is a result of aerobic respiration. heavy breathing during exercise has produced a carbon dioxide surplus in her muscles. lactate is being transported to her liver. this is a result of aerobic respiration. strenuous exercise has caused her body to be in carbon dioxide debt, and she is breathing hard while lactate is transported to the liver. this is a result of anaerobic respiration. strenuous exercise has caused her body to be in oxygen debt, and she is breathing hard while lactate is transported to the liver. this is a result of anaerobic respiration.