What are essential elements? How many elements are reported from plants?

Explanation

### Step-by-Step Solution

1. **Definition of Essential Elements**:
- Essential elements are chemical nutrients that are necessary for the successful growth and development of plants. These elements play crucial roles in various physiological processes within the plant.

2. **Classification of Essential Elements**:
- Essential elements can be classified into two categories: macronutrients and micronutrients.

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