which gas in earths atmosphere helps living things make proteins?\noxygen\nnitrogen\nwater vapor\ncarbon…

Brief Explanations:

Proteins contain nitrogen. Nitrogen gas in the atmosphere is converted into forms usable by living - things through processes like nitrogen - fixation, which is then incorporated into proteins. Oxygen is for respiration, water vapor is related to the water cycle, and carbon dioxide is used in photosynthesis.

Answer:

B. nitrogen