Twin characteristics of growth are

Options

A. Decrease in mass and increase in number
B. Increase in mass and decrease in number
C. Decrease in mass and number
D. Increase in mass and number

Explanation

To answer the question "Twin characteristics of growth are," we need to identify the correct characteristics that define growth in living organisms. Let's break down the solution step by step:

### Step-by-Step Solution:

1. **Understanding Growth**: Growth in biological terms refers to an increase in size or mass of an organism. It is a fundamental characteristic of living organisms.

2. **Identifying Twin Characteristics**: The term "twin characteristics" suggests that there are two key aspects of growth that occur simultaneously. These are:
- **Increase in Mass**: This refers to the accumulation of cellular material, leading to a larger body size.
- **Increase in Number**: This refers to the increase in the number of cells, which contributes to the overall growth of the organism.

3. **Mechanism of Growth**: The increase in mass and number is primarily due to cell division. As cells divide, they contribute to both the mass of the organism and the total number of cells.

4. **Evaluating Options**: The options provided are:
- A) Decrease in mass and increase in number
- B) Increase in mass and decrease in number
- C) Decrease in mass and number
- D) Increase in mass and number

We analyze each option:
- Option A is incorrect because growth does not involve a decrease in mass.
- Option B is incorrect because growth involves an increase in both mass and number, not a decrease in number.
- Option C is incorrect as it suggests a decrease in both mass and number, which is not characteristic of growth.
- Option D is correct as it accurately reflects the twin characteristics of growth: an increase in both mass and number.

5. **Conclusion**: Therefore, the correct answer to the question is **D) Increase in mass and number**.