What is nebenkern?

Explanation

### Step-by-Step Solution:

1. **Definition of Nebenkern**: Nebenkern is a term that refers to a specific structure associated with mitochondrial formation in certain organisms, particularly in insects like Drosophila.

2. **Origin of the Term**: The term "Nebenkern" is derived from German, where "neben" means "beside" and "kern" means "nucleus." It indicates a structure that is associated with the nucleus in the context of sperm development.

3. **Function of Nebenkern**: The primary function of the Nebenkern is to provide energy for the motility of sperm cells. This energy is crucial for the sperm to swim towards and fertilize the egg.

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