Which one of the following is one of the characteristics of a biological community?

Options

A. Sex-ratio
B. Stratification
C. Natality
D. Mortality

Answer

### Step-by-Step Solution:

1. **Understanding Biological Community**:
- A biological community consists of different species living and interacting within a specific geographical area. It includes all the organisms that coexist in that environment.

2. **Analyzing the Options**:
- The question presents several options, and we need to identify which one is a characteristic of a biological community.

3. **Evaluating Each Option**:
- **Option A: Sex Ratio**: This refers to the ratio of males to females in a population. While it is important in population studies, it does not define a biological community, so this option is incorrect.
- **Option B: Stratification**: This describes the vertical layering of vegetation in an ecosystem. It indicates how different plant species grow at various heights, which is a significant characteristic of a biological community as it allows for diverse organisms to coexist. This option is correct.
- **Option C: Natality**: This is the birth rate in a population. While it is relevant to population dynamics, it does not specifically characterize a biological community, making this option incorrect.
- **Option D: Mortality**: This refers to the death rate in a population. Similar to natality, it is not a defining characteristic of a biological community, so this option is also incorrect.

4. **Conclusion**:
- After evaluating all the options, the correct answer is **Option B: Stratification**, as it is a characteristic of a biological community.