Define speciation.

Explanation

### Step-by-Step Solution:

1. **Understanding Speciation**:
- Speciation is the evolutionary process through which new biological species arise. It involves the divergence of a single species into two or more distinct species.

2. **Types of Speciation**:
- There are four main types of speciation:
- **Allopatric Speciation**: This occurs when a population is geographically separated by a physical barrier (like mountains or rivers), leading to reproductive isolation and eventually the formation of new species.
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