`"__________"` `"__________"` and `"_________"` are the three main elements usually supplied in chemical fertilisers.

Explanation

To answer the question regarding the three main elements usually supplied in chemical fertilizers, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements**: The question asks for three main elements found in chemical fertilizers. We need to recall the essential nutrients that are commonly included in these fertilizers.

2. **List the Elements**: The three main elements that are typically supplied in chemical fertilizers are:
- **Nitrogen (N)**
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