What is the main absorption form of nitrogen ?

Explanation

**Step-by-Step Solution:**

1. **Understanding the Importance of Nitrogen**: Nitrogen is essential for the growth and development of plants. It plays a crucial role in the formation of amino acids, proteins, and nucleic acids.

2. **Absorption of Nitrogen**: Plants cannot absorb nitrogen directly from the atmosphere. The atmospheric nitrogen (N₂) is not in a form that plants can utilize.

3. **Nitrogen Fixation**: To make nitrogen available to plants, a process called nitrogen fixation occurs. During this process, atmospheric nitrogen is converted into a more usable form.

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