Susceptibility to extinction is due to

Options

A. large body size
B. small population
C. high trophic level
D. All the three

Answer

### Step-by-Step Solution:

1. **Understanding the Concept of Extinction**:
- Extinction occurs when a species no longer exists. Certain characteristics of species can make them more vulnerable to extinction.

2. **Analyzing the Options**:
- **Option A: Large Body Size**:
- Large-bodied animals often have fewer natural predators, but they can be more visible to hunters and may require larger territories for food and reproduction. This makes them more susceptible to extinction due to habitat loss and hunting.
- **Option B: Small Population Size**:
- Species with small populations are at a higher risk of extinction because if a few individuals die, it significantly impacts the overall population. This can lead to inbreeding and reduced genetic diversity, further increasing extinction risk.
- **Option C: High Trophic Level**:
- Species at higher trophic levels (like top predators) tend to have smaller populations because they require more energy and resources. They are also more affected by changes in the ecosystem, such as loss of prey or habitat, making them more susceptible to extinction.

3. **Conclusion**:
- All three options (A, B, and C) contribute to the susceptibility of species to extinction. Therefore, the correct answer is **D: All three are correct**.