As the number of individuals approaches the carrying capacity of a population, which of the following is predicted by the sigmoidal growth curve?

Options

A. Population biomass will remain the same
B. Population density will increase.exponentially
C. Population growth rate will decrease
D. Population growth rate will increase

Answer

To answer the question regarding what is predicted by the sigmoidal growth curve as the number of individuals approaches the carrying capacity of a population, we will analyze the options provided and the characteristics of the sigmoid growth curve.

### Step-by-Step Solution:

1. **Understanding the Sigmoidal Growth Curve**: The sigmoid growth curve, also known as the logistic growth curve, describes how a population grows in an environment with limited resources. It consists of three phases: lag phase, exponential growth phase, and stationary phase.

2. **Identifying the Carrying Capacity**: The carrying capacity (K) is the maximum population size that an environment can sustain indefinitely. As the population size (N) approaches K, the growth rate of the population changes.

3. **Analyzing the Growth Rate**:
- In the **lag phase**, the population grows slowly.
- In the **exponential phase**, the population grows rapidly.
- As the population approaches the carrying capacity, the growth rate begins to slow down due to limited resources.

4. **Evaluating the Options**:
- **Option 1**: "Population biomass will remain the same." - This is incorrect; biomass can change as the population grows.
- **Option 2**: "Population density will increase exponentially." - This is incorrect; population density does not continue to increase exponentially as it approaches carrying capacity.
- **Option 3**: "Population growth rate will decrease." - This is correct; as the population approaches K, the growth rate decreases due to resource limitations.
- **Option 4**: "Population growth will increase." - This is incorrect; growth does not continue to increase as it nears carrying capacity.

5. **Conclusion**: The correct answer is **Option 3**: "Population growth rate will decrease."