Biology

True.

Plants and animals cannot use nitrogen directly from the air because atmospheric nitrogen exists as N₂ (a nitrogen molecule made of two nitrogen atoms), which is very stable and not reactive.

To be usable by plants and animals, nitrogen needs to be in a more reactive form, such as nitrates (NO₃⁻) or ammonia (NH₃). Plants typically take up nitrogen in the form of nitrates or ammonium ions from the soil. Animals, in turn, obtain nitrogen by consuming plants or other animals.