The nitrogen utilized by most plants is derived from

a. soil.
b. the atmosphere.
c. nitrogen gas.
d. decayed organic matter

I think the correct answer from the choices listed above is option A. The nitrogen utilized by most plants is derived from the soil. Nitrogen is a component of chlorophyll and therefore essential for photosynthesis. Plants use nitrogen by absorbing either nitrate or ammonium ions through the roots.

The Danube river? Cuz if it’s the Danube river then it’s because it provides an important source of water for agriculture and drinking, and it allows for transportation of people and goods.