Read the following statements and select the correct ones.
(i) Increase in mass and increase in number of individuals are twin characteristics of growth.
(ii) Metabolic reactions can be demonstrated outside the body in isolated cell-free systems.
(iii) 'Response to stimuli' is a defining property of living organisms.

Options

A. (i) and (ii)
B. (ii) and (iii)
C. (i) and (iii)
D. (i), (ii) and (iii)

Answer

To determine which statements are correct, let's analyze each one step by step.

### Step 1: Analyze Statement (i)
The first statement claims that "Increase in mass and increase in number of individuals are twin characteristics of growth."
- **Explanation**: Growth in living organisms can be defined in two ways:
1. **Increase in Mass**: This occurs due to cell division and the accumulation of cellular materials.
2. **Increase in Number of Individuals**: This is achieved through reproduction, which leads to an increase in the population size.
- **Conclusion**: Both aspects are indeed characteristics of growth. Therefore, this statement is **correct**.

### Step 2: Analyze Statement (ii)
The second statement states that "Metabolic reactions can be demonstrated outside the body in isolated cell-free systems."
- **Explanation**: Metabolic reactions involve biochemical processes that can occur in living organisms. However, these reactions can also be studied in vitro (outside of a living organism) using isolated cell-free systems, such as test tubes or biochemical assays.
- **Conclusion**: This statement is also **correct** as it is possible to demonstrate metabolic reactions in such systems.

### Step 3: Analyze Statement (iii)
The third statement asserts that "'Response to stimuli' is a defining property of living organisms."
- **Explanation**: All living organisms, including plants and animals, have the ability to respond to environmental stimuli. This characteristic is essential for survival and adaptation.
- **Conclusion**: This statement is **correct** as well.

### Final Conclusion
After analyzing all three statements:
- Statement (i) is correct.
- Statement (ii) is correct.
- Statement (iii) is correct.

Thus, all three statements are correct.

### Answer:
All statements (i), (ii), and (iii) are correct.

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