Name the process responsible for energy production in the sun.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of the process responsible for energy production in the sun.

2. **Identifying the Process**: The primary process that generates energy in the sun is nuclear fusion. This involves the combination of lighter atomic nuclei to form a heavier nucleus.

3. **Explaining Nuclear Fusion**: In the sun, hydrogen isotopes such as deuterium and tritium (which are lighter nuclei) undergo fusion. When these isotopes combine, they form a heavier nucleus, typically helium, and release a significant amount of energy in the process.

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