Which of the following is the first phase to occur in a sigmoid growth curve?

Options

A. Log phase
B. Lag phase
C. Exponential phase
D. Deceleration phase

Answer

To determine the first phase to occur in a sigmoid growth curve, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Sigmoid Growth Curve**:
- A sigmoid growth curve, also known as an S-shaped growth curve, represents how populations grow over time when resources are limited.

2. **Identifying the Phases of the Sigmoid Growth Curve**:
- The sigmoid growth curve consists of three main phases:
- **Lag Phase**: This is the initial phase where the population is adapting to the environment. During this phase, growth is minimal as the organisms are adjusting.
- **Log Phase**: Following the lag phase, the population experiences rapid growth as resources are abundant.
- **Stationary Phase**: Eventually, the growth rate slows down as resources become limited, leading to a stabilization of the population size.

3. **Determining the First Phase**:
- The question specifically asks for the first phase in the sigmoid growth curve. Based on the definitions:
- The **Lag Phase** is the first phase where the population is adapting and growth is slow.
- The **Log Phase** follows the lag phase and is characterized by rapid growth.
- The **Stationary Phase** comes last when resources are limited.

4. **Conclusion**:
- Therefore, the first phase to occur in a sigmoid growth curve is the **Lag Phase**.

### Final Answer:
The first phase to occur in a sigmoid growth curve is the **Lag Phase**.