Select the incorrect statement among the following.

Options

A. Increase in growth per unit time is growth rate.
B. A sigmoid growth curve is a characteristic of most living organsims in their natural environment.
C. Rate of growth is constant during geometrical growth.
D. Exponential phase is also called as log phase.

Explanation

To determine the incorrect statement among the given options, we will analyze each statement step by step.

### Step 1: Analyze the First Statement
**Statement**: "Increase in growth per unit time is called as growth rate."
- **Analysis**: This statement is correct. Growth rate is defined as the increase in size or mass of an organism or part of an organism per unit time.

### Step 2: Analyze the Second Statement
**Statement**: "A sigmoid curve is characteristic of most of the living organisms living in natural environment."
- **Analysis**: This statement is also correct. A sigmoid (S-shaped) growth curve is typical for populations in natural environments, showing phases of slow growth, rapid growth, and then leveling off as resources become limited.

### Step 3: Analyze the Third Statement
**Statement**: "Rate of growth is constant during geometrical growth."
- **Analysis**: This statement is incorrect. During geometrical growth, the rate of growth is not constant; it increases exponentially as the number of cells doubles at each division. For example, if one cell divides into two, then four, then eight, the growth rate accelerates.

### Step 4: Analyze the Fourth Statement
**Statement**: "The exponential phase is also called as the log phase."
- **Analysis**: This statement is correct. The exponential phase of growth, where the population grows at its maximum rate, is often referred to as the log phase due to the logarithmic nature of the growth curve.

### Conclusion
After analyzing all four statements, we find that the **third statement** is the incorrect one. The rate of growth during geometrical growth is not constant; it increases over time.

### Final Answer
The incorrect statement is: **"Rate of growth is constant during geometrical growth."**

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