Ratio between mortality and natality is :

Options

A. vital index
B. population density
C. total count
D. none of these

Answer

To solve the question about the ratio between mortality and natality, we can follow these steps:

### Step-by-Step Solution:

1. **Define Mortality and Natality**:
- **Mortality** refers to the death rate in a population, which is the average number of individuals that die per unit of time (usually per year).
- **Natality** refers to the birth rate in a population, which is the average number of individuals born per unit of time (also usually per year).

2. **Understand the Ratio**:
- The question asks for the ratio between mortality and natality. This ratio can be expressed mathematically as:
\[ \text{Ratio} = \frac{\text{Mortality}}{\text{Natality}} \]

3. **Identify the Term for the Ratio**:
- The ratio of mortality to natality is commonly referred to as the **Vital Index**. The Vital Index is a measure that helps in understanding the growth of a population.

4. **Clarify the Options**:
- The options provided are:
1. Vital Index
2. Population Density
3. Total Count
4. None of these
- Since we have established that the ratio of mortality to natality is called the Vital Index, we can conclude that this is the correct answer.

5. **Conclusion**:
- Therefore, the answer to the question is **Vital Index**.

### Final Answer:
The ratio between mortality and natality is called the **Vital Index**.

---