`((K-N))/K` represents

Options

A. carrying capacity
B. environmental resistance
C. vital index
D. crash phase

Answer

To solve the question regarding what the expression \((K-N)/K\) represents, we can break it down step by step:

### Step-by-Step Solution:

1. **Understanding the Variables**:
- In the expression \((K-N)/K\):
- \(K\) represents the carrying capacity of the environment. This is the maximum population size that the environment can sustain indefinitely.
- \(N\) represents the current population size.

2. **Interpreting the Expression**:
- The expression \((K-N)\) calculates the difference between the carrying capacity and the current population size. This difference indicates how many more individuals the environment can support before reaching its carrying capacity.
- Dividing by \(K\) normalizes this difference to a fraction of the carrying capacity, giving a relative measure of how close the current population is to the carrying capacity.

3. **Relating to Population Dynamics**:
- In the context of logistic population growth, the expression \((K-N)/K\) is used to describe the growth rate of a population as it approaches its carrying capacity.
- As the population size \(N\) increases and approaches \(K\), the value of \((K-N)/K\) decreases, indicating that the environment is becoming more saturated and that growth will slow down due to limited resources.

4. **Identifying the Concept**:
- The expression is indicative of **environmental resistance**, which encompasses the factors that limit population growth as it nears the carrying capacity. These factors can include limited resources, competition, predation, and disease.

5. **Conclusion**:
- Therefore, the expression \((K-N)/K\) represents **environmental resistance** in the context of logistic population growth.

### Final Answer:
The expression \((K-N)/K\) represents **environmental resistance**.