Why plants can’t use nitrogen directly in spite it’s presence in the atmosphere up to 78% by volume?

Why plants can’t use nitrogen directly in spite it’s presence in t

1.	Why plants can’t use nitrogen directly in spite it’s presence in the atmosphere up to 78% by volume?
Answer» A plant can not use atmospheric nitrogen directly because it is present in free gaseous form in the atmosphere whereas plants are capable of absorbing in the form of nitrogen compounds only from the soil. In soil, nitrogen is found in the form of organic and inorganic compounds and is absorbed by the roots.