Akey to gas exchange is that both co₂ and o₂ flow along their respective concentration gradients (from high concentrations to low concentrations). an important consideration to how efficiently gas exchange can occur is the relative concentration of environmental oxygen to the oxygen in the tissues. is true.

this is true about respiration (inhalation and exhalation)

Explanation:

inhalation is the exchange of gas from the environmental oxygen to the oxygen in the tissues.

while Exhalation is the gas exchange of CO2 with O2 (the CO2 is exhales from high concentration to the environment of low concentration.

1.solid

2.carbon dioxide

3.helium