Stinging hair of nettle leaves inject ..... causing burning pain.

Options

A. ethanolo acid
B. methanolc acid
C. propanolc acid
D. butanoic acid

Explanation

To solve the question "Stinging hair of nettle leaves inject ..... causing burning pain," we need to identify the substance responsible for the burning sensation caused by the stinging hairs of nettle leaves.

### Step-by-Step Solution:

1. **Understanding the Question**: The question refers to the stinging hairs of nettle leaves and asks what substance is injected that causes a burning pain.

2. **Identifying the Plant**: Nettle leaves are known for their stinging hairs, which can cause a painful sensation upon contact.

3. **Researching the Cause of Pain**: The burning pain associated with nettle stings is due to the release of certain chemicals when the stinging hairs penetrate the skin.

4. **Identifying the Chemical**: The primary chemical responsible for the burning sensation from nettle stings is methanoic acid, commonly known as formic acid. Its chemical formula is HCOOH.

5. **Conclusion**: Therefore, the answer to the question is that the stinging hair of nettle leaves injects **methanoic acid (formic acid)**, causing burning pain.

### Final Answer:
Stinging hair of nettle leaves inject **methanoic acid (formic acid)** causing burning pain.

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