Radioactive C-dating and living fossils are used for.

Options

A. Biological age
B. Geological age
C. Age of Rock
D. Geographical distribution

Answer

### Step-by-Step Solution:

1. **Understanding Radioactive Carbon Dating**:
- Radioactive carbon dating, commonly known as carbon dating, is a method used to determine the age of organic materials. It measures the amount of carbon-14, a radioactive isotope of carbon, remaining in a sample. This technique is particularly useful for dating materials that are up to about 50,000 years old.

2. **Understanding Living Fossils**:
- Living fossils are species that have remained relatively unchanged over long geological periods and closely resemble species known only from the fossil record. They provide insights into evolutionary history and the conditions of past environments.

3. **Purpose of Radioactive Carbon Dating**:
- The primary use of radioactive carbon dating is to establish the biological age of organic remains. By determining how much carbon-14 is left in a sample, scientists can estimate when the organism died.

4. **Purpose of Living Fossils**:
- Living fossils help scientists understand evolutionary processes and the historical distribution of species. They serve as a link between past and present ecosystems, allowing researchers to study how certain species have survived through significant changes in the environment.

5. **Conclusion**:
- Both radioactive carbon dating and the study of living fossils are essential for understanding the biological age of organisms and the geological age of the rocks in which fossils are found. They are crucial tools in the field of paleontology and evolutionary biology.

### Final Answer:
Radioactive carbon dating is used to determine the biological age of organic materials, while living fossils provide insights into evolutionary history and the age of geological formations.

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