Although greenhouse gases such as water vapor, CO2, and methane naturally occur in smaller amounts, they absorb and release heat energy more efficiently than gases like N and O. (Nitrogen and Oxygen.)
So I would say (1) is the answer
the number of molecules in a certain substance
It comes from a unicellular organism named Chloroplast that produces a green pigment substance called chlorophyll, this where oxygen is produced as a by-product of photosynthesis.
