A stands out most to me, CO comes from the air and air is basically oxygen we breath. When we exhale CO comes out (of course). I would say A is correct.
Glycolysis, Krebs cycle, electron transport chain
Answer:
Mass does not affect gravity and distance has an indirect relationship.
Explanation:
The equation for gravity is, g = 
where, G = gravitational constant
M = mass of the planet
R = distance between the bodies (object and center of planet)
so, gravity depends on the mass of planet, not on mass of object
and is inversely proportional to sqaure of distance.