A population characteristic of a species susceptible to extinction is

Options

A. Low trophic level in food chain
B. Inability to switch over to alternate food source
C. Wide range of distribution
D. High biotic potential

Answer

To determine the population characteristic of a species that is susceptible to extinction, we can analyze the options provided:

1. **Low Trophic Level in Food Chain**: Species at lower trophic levels (like primary producers) generally have more individuals and are less susceptible to extinction because they are foundational to the ecosystem.

2. **Inability to Switch Over to Alternate Food Source**: Species that cannot adapt to new food sources when their primary source is threatened are indeed more susceptible to extinction. This inability to adapt can lead to population decline and eventual extinction.

3. **Wide Range of Distribution**: Species with a wide distribution are often less susceptible to extinction because they can thrive in various habitats and are less affected by localized changes in the environment.

4. **High Biotic Potential**: Species with high biotic potential can reproduce quickly and in large numbers, which can help sustain their populations even in adverse conditions.

Based on this analysis, the characteristic that makes a species more susceptible to extinction is the **inability to switch over to an alternate food source**. This characteristic limits the species' adaptability and survival in changing environments.

### Step-by-Step Solution:
1. **Identify the Characteristics**: Review the characteristics provided in the question.
2. **Analyze Each Characteristic**: Assess how each characteristic affects the likelihood of extinction.
3. **Determine the Most Susceptible Characteristic**: Conclude which characteristic is most directly linked to increased extinction risk.
4. **Select the Correct Answer**: Choose the option that represents the characteristic that makes a species more susceptible to extinction.