Increase in mass and increase in number of individuals are twin characteristics of which character of living organisms?

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the characteristics of living organisms that involve an increase in mass and an increase in the number of individuals.

2. **Defining Key Terms**:
- **Mass**: Refers to the weight or size of an organism. In biological terms, it often relates to the overall growth of an organism.
- **Number of Individuals**: This refers to the population size or the number of organisms in a particular species.

3. **Identifying the Concept**: The question hints at a fundamental biological concept that encompasses both an increase in mass and an increase in the number of individuals.

4. **Recognizing the Term**: The term that encompasses both an increase in mass and an increase in the number of individuals is **growth**. Growth in biology refers to the process by which organisms increase in size and mass, as well as the reproduction that leads to an increase in the number of individuals.

5. **Explaining Growth**:
- Growth can be observed in individual organisms as they develop from a zygote to an adult through cell division and differentiation.
- In terms of populations, growth can occur through reproduction, leading to an increase in the number of individuals.

6. **Conclusion**: Therefore, the twin characteristics of an increase in mass and an increase in the number of individuals can be defined by the term **growth**.

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