Question

how do humans get nitrogen into our bodies to build macromolecules (like proteins and dna)? by breathing in nitrogen gas from the atmosphere. by eating food from plant or animal sources by absorbing nitrogen directly through our skin. by drinking water that contains dissolved nitrogen gas.

Explanation:

Humans cannot directly use atmospheric nitrogen. Nitrogen - fixing bacteria convert atmospheric nitrogen into forms that plants can use. Plants incorporate these nitrogen - containing compounds into their tissues. Animals, including humans, obtain nitrogen by consuming plants or other animals that have consumed plants. Skin absorption of nitrogen is not a significant route for nitrogen intake, and the nitrogen in water is not in a form readily usable for building macromolecules.

Answer:

By eating food from plant or animal sources