For gas exchange to be efficient, the respiratory membrane must be
a. between 5 and 6 micrometers thick.
b. at least 3 micrometers thick.
c. 0.5 to 1 micrometer thick.
d. the thickness of the respiratory membrane is not important in the efficiency of gas exchange. 4 points

C. 0,5 to 1 micrometer thick.

Explanation:

For an efficient gas exchange, the respiratory membrane must be 0,5 to 1 micrometer thick. That way gases are able to penetrate the membrane and get to the blood capilar as fast as possible. If the respiratory membrane was thicker, gases do not penetrate and go through the membrane as fast and efficient as in the previous case.

answer; i believe that the correct answer is (essential amino acids);