What causes the extinction of species?

Explanation

### Step-by-Step Text Solution:

1. **Definition of Extinction**: Extinction refers to the complete disappearance of a species from the Earth. This occurs when the population of a species declines to the point where no individuals are left.

2. **Habitat Loss**: One of the primary causes of extinction is habitat loss. This occurs when natural environments, such as forests, are destroyed or altered, often due to human activities like deforestation. When animals and plants lose their homes, they struggle to survive.

3. **Introduction of Exotic Species**: The introduction of new species into an ecosystem can also lead to extinction. Exotic species, which are species brought from other regions, can disrupt the balance of the local ecosystem. They may outcompete native species for resources, leading to a decline in the native populations.

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