The double helical molecular model of DNA was given by Watson and Crick. But .DNA is double stranded. was suggested by

Options

A. Hershey and Chase
B. Wilkins and Franklin
C. Griffith
D. Avery

Answer

To answer the question regarding who suggested that DNA is double-stranded, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question states that Watson and Crick proposed the double helical structure of DNA. However, it asks who suggested that DNA is double-stranded.

2. **Identifying Key Scientists**: We need to consider the contributions of various scientists in the field of molecular biology and DNA structure. The options provided are Hershey and Chase, Wilkins and Franklin, Griffith, and Avery.

3. **Analyzing Contributions**:
- **Hershey and Chase**: They conducted experiments that demonstrated DNA is the genetic material but did not specifically address the double-stranded nature of DNA.
- **Wilkins and Franklin**: Rosalind Franklin used X-ray crystallography to obtain images of DNA, which provided crucial evidence for its double helical structure. Their work was instrumental in suggesting that DNA is double-stranded.
- **Griffith**: He is known for his work on bacterial transformation but did not contribute to the understanding of DNA's structure.
- **Avery**: He showed that DNA was the key component in Griffith's experiments but did not address the double-stranded nature of DNA.

4. **Conclusion**: Based on the analysis, the correct answer is **Wilkins and Franklin**, as their work with X-ray diffraction images led to the understanding that DNA is double-stranded.

### Final Answer:
The suggestion that DNA is double-stranded was made by **Wilkins and Franklin**.