Weegy: B.)Nitrogen fixation converts atmospheric nitrogen into ammonium, which plants absorb. The plants, by assimilation , incorporate the ammonium into proteins. User: Although nitrogen gas makes up 78% of the atmosphere, we can't use it because _____.
nitrogen gas is explosive
we must absorb it through the soil
nitrogen atoms must be broken apart first
we must absorb it through the sun
Weegy: nitrogen atoms must be broken apart first ... (More)