Question

question 59
all living things need nitrogen. how does nitrogen enter the living portion of an ecosystem?
○ elemental nitrogen taken in by plant roots
○ atmospheric n₂ taken in by soil bacteria
○ atmospheric n₂ taken in by photosynthesis
○ elemental nitrogen taken in by plant leaves

Explanation:

Plants cannot directly take in atmospheric \(N_2\). Soil bacteria (such as Rhizobium) can fix atmospheric \(N_2\) (convert it into forms like ammonia) which plants can then use. Elemental nitrogen (\(N_2\)) is not taken in by plant roots or leaves in a usable form for most plants. Photosynthesis is mainly about carbon - dioxide, water, and producing glucose and oxygen, not about taking in \(N_2\).

Answer:

Atmospheric \(N_2\) taken in by soil bacteria.