The term 'Nuclein' for the genetic material was used by:

Options

A. Franklin
B. Meischer
C. Chargaff
D. Mendel

Answer

To solve the question regarding who first used the term 'Nuclein' for genetic material, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the scientist who first introduced the term 'Nuclein' in relation to genetic material.

2. **Historical Context**: It is important to note that the understanding of genetic material has evolved over time. Initially, scientists were not aware of the structure of DNA and referred to it by different names.

3. **Identifying Key Figures**: We need to look for scientists who contributed to the early understanding of genetic material. The transcript mentions several scientists, including Friedrich Meischer, Rosalind Franklin, Watson and Crick, Erwin Chargaff, and Gregor Mendel.

4. **Friedrich Meischer's Contribution**: According to the transcript, Friedrich Meischer was the scientist who, in 1869, observed an acidic molecule found in the nucleus and named it 'Nuclein'. This is a crucial piece of information as it directly answers the question.

5. **Eliminating Other Options**: The other scientists mentioned (Franklin, Watson, Crick, Chargaff, and Mendel) contributed to the understanding of DNA and genetics, but they did not use the term 'Nuclein'. For instance, Rosalind Franklin worked on the structure of DNA, while Watson and Crick proposed the double helix model much later.

6. **Final Answer**: Based on the information gathered, the correct answer to the question is Friedrich Meischer.

### Conclusion:
The term 'Nuclein' for the genetic material was first used by Friedrich Meischer.

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