Biology

The correct path that nitrogen could take is:

C.air → bacteria → plants → animals

Here’s why this is the correct sequence:

1.Air: Nitrogen in the atmosphere is mostly in the form of N₂, which is not directly usable by plants or animals.

2.Bacteria: Certain bacteria, such as nitrogen-fixing bacteria, convert atmospheric nitrogen (N₂) into usable forms like ammonia (NH₃) or nitrates (NO₃⁻). This is known as nitrogen fixation. These bacteria either live in the soil or in a symbiotic relationship with plants (such as in legume root nodules).