Give an example of an organism that enters 'diapause' and why.

Explanation

**Step-by-Step Solution:**

1. **Understanding Diapause**: Diapause is a state of suspended development that some organisms enter in response to unfavorable environmental conditions. It is a survival strategy that allows them to withstand adverse situations such as extreme temperatures or lack of food.

2. **Identifying an Organism**: An example of an organism that enters diapause is the **zooplankton**. Zooplankton are small, often microscopic animals that live in water bodies such as lakes and oceans.

3. **Reason for Entering Diapause**: Zooplankton enter diapause to survive unfavorable conditions. For instance, during winter, when temperatures drop and food becomes scarce, zooplankton can suspend their development and metabolic activities. This allows them to conserve energy and survive until conditions improve.

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