Name the form of energy which a wound up watch spring possesses.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the form of energy possessed by a wound-up watch spring.

2. **Identifying the Energy Type**: A wound-up spring stores energy due to its position. This energy is not in motion but is stored because of the spring being compressed or stretched.

3. **Defining Potential Energy**: The energy stored in the spring is called potential energy. Specifically, in this case, it is elastic potential energy, which is the energy stored in elastic materials as the result of their stretching or compressing.

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