How many sigma-bonds are present in ` CH_3 - CH_3` ?

Explanation

To determine the number of sigma bonds in ethane (CH₃-CH₃), we can follow these steps:

### Step-by-Step Solution:

1. **Draw the Structure of Ethane:**
Ethane consists of two carbon atoms connected by a single bond, with each carbon atom bonded to three hydrogen atoms. The structural formula can be represented as:
```
H H
...