State one relevant observation for the following:
Nitric oxide comes in contact with atmosphere.

Explanation

To answer the question, we need to state one relevant observation when nitric oxide (NO) comes in contact with the atmosphere, which contains oxygen (O₂).

### Step-by-Step Solution:

1. **Identify the Reaction**: When nitric oxide (NO) comes into contact with oxygen in the atmosphere, a chemical reaction occurs. The primary reaction is:
\[ 2 \, \text{NO} + \text{O}_2 \rightarrow 2 \, \text{NO}_2 \]
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