The answer is: beans and whey protein
The most abundant element in the atmosphere is nitrogen N2 (~78%), followed by oxygen O2 (~21%).
CO2 makes up less than 1% of the atmosphere. Much less for that matter.
The key to the question is knowing that protein contains nitrogen.
Protein is a macromolecule made up of smaller molecules called amino acids. Amino acids are made up of a central carbon (C) and 4 groups:
amine (-NH2)
carboxylic acid (-COOH)
a hydrogen (H)
a side chain which is different and specific to each amino acid
One can infer amino acids contain nitrogen from their name (amino).
Beans contain a high amount of protein, and whey protein is a type of protein, so both contain nitrogen.