Brood parasitism occurs in ___________.

Explanation

### Step-by-Step Solution:

1. **Understanding Parasitism**:
- Parasitism is a biological interaction where one organism (the parasite) benefits at the expense of another organism (the host). The parasite relies on the host for food, nutrition, and sometimes shelter.

2. **Defining Brood Parasitism**:
- Brood parasitism is a specific type of parasitism where a parasitic bird lays its eggs in the nest of a host bird. The host bird then incubates and raises the eggs, often without realizing that they are not its own.

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