Animals having multiple or numerous setae are included under

Options

A. Polychaeta
B. Oligochaeta
C. Hirudinea
D. Onychophora

Answer

To solve the question "Animals having multiple or numerous setae are included under," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Classification of Annelids**:
- Annelids are segmented worms that belong to the phylum Annelida. They are characterized by the presence of setae (bristle-like structures) on their body segments.

2. **Identify the Classes of Annelids**:
- The phylum Annelida is divided into three main classes:
- **Polychaeta**: These are annelids that have numerous setae.
- **Oligochaeta**: These annelids have a few setae.
- **Hirudinea**: This class includes leeches, which typically lack setae.

3. **Analyze the Options**:
- **Option 1: Polychaeta** - This class is characterized by having many setae. Examples include marine worms like Nereis.
- **Option 2: Oligochaeta** - This class has fewer setae, with earthworms being a common example.
- **Option 3: Hirudinea** - This class lacks setae entirely, with leeches as examples.
- **Option 4: Onychophora** - This is a different phylum altogether, known for velvet worms, and is not related to annelids.

4. **Determine the Correct Answer**:
- Since the question specifically asks for animals with multiple or numerous setae, the correct answer is **Polychaeta**.

### Final Answer:
Animals having multiple or numerous setae are included under **Polychaeta**.

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