If a molecule of co2 released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except if a molecule of released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except
a) the pulmonary vein.
b) an alveolus.
c) the right ventricle.
d) the right atrium.
e) the trachea.

a) the pulmonary vein

Explanation:

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme