Living beings maintain continuity of life by:

Options

A. Adaptation
B. DNA-replication and its transfer in next generation
C. RNA synthesis
D. None of the above

Answer

To solve the question "Living beings maintain continuity of life by:", we will analyze each option provided and determine which one is the most accurate.

### Step-by-Step Solution:

1. **Understanding the Concept of Continuity of Life**:
- Continuity of life refers to the ability of living organisms to reproduce and pass on their genetic material to the next generation. This is essential for the survival of species over time.

2. **Analyzing Option A: Adaptation**:
- Adaptation is the process by which organisms adjust to their environment. While adaptation is important for survival in changing environments, it does not directly contribute to the continuity of life. It helps species survive but does not ensure the transfer of genetic material to the next generation.

**Hint**: Consider how adaptation affects survival versus reproduction.

3. **Analyzing Option B: DNA Replication or its Transfer in Next Generation**:
- DNA replication is the process by which a cell makes a copy of its DNA. This is crucial for reproduction, as it ensures that genetic information is passed on to offspring. The transfer of DNA to the next generation is fundamental to maintaining continuity of life, as it allows for the inheritance of traits.

**Hint**: Think about how genetic information is passed from parents to offspring.

4. **Analyzing Option C: RNA Synthesis**:
- RNA synthesis is involved in protein production and plays a role in gene expression. However, RNA alone does not maintain continuity of life; it is the DNA that carries the genetic blueprint necessary for reproduction.

**Hint**: Reflect on the role of RNA in relation to DNA in the context of reproduction.

5. **Analyzing Option D: None of the Above**:
- This option suggests that none of the previous options are correct. However, since DNA replication is essential for the continuity of life, this option is not valid.

**Hint**: Evaluate if any of the previous options can be considered correct.

6. **Conclusion**:
- After analyzing all the options, the correct answer is **Option B: DNA replication or its transfer in next generation**. This process is essential for the continuity of life as it allows for the inheritance of genetic material.

### Final Answer:
**B. DNA replication or its transfer in next generation.**