Which of the following scientist's contributions to viruses is correctly matched ?
I . M.W Beijerinek demonstrated that the extract of the infected plants of tobacco mosaic could cause infection in healthy plants and called the fluid as contagium vivum fluidum (infection living fluid )
II. W. M. Stanley showed that viruses could be crystallized and crystals consist venom or proteins.
III.The name virus that means venom or poisonous fluid was given by Dmitri lvanowsky.

Options

A. I and II
B. I and III
C. II and III
D. I , II and III

Answer

To solve the question regarding the contributions of scientists to the study of viruses, we will analyze each statement provided:

### Step-by-Step Solution:

1. **Statement I: M.W. Beijerinck's Contribution**
- M.W. Beijerinck conducted experiments with the tobacco mosaic virus. He demonstrated that the extract from infected tobacco plants could cause infection in healthy plants. He referred to this infectious fluid as "contagium vivum fluidum," which translates to "infectious living fluid."
- **Conclusion**: This statement is correct.

2. **Statement II: W.M. Stanley's Contribution**
- W.M. Stanley is known for his work on the crystallization of viruses. He was able to crystallize the tobacco mosaic virus and showed that these crystals were primarily composed of proteins, not venom.
- **Conclusion**: This statement is also correct, but it is important to note that the term "venom" is misleading in this context; the crystals consist of proteins.

3. **Statement III: Dmitri Ivanovsky's Contribution**
- Dmitri Ivanovsky is credited with the discovery of viruses. He was the first to use the term "virus," which means "poison" or "venom." He conducted his work in 1892, focusing on the tobacco mosaic disease.
- **Conclusion**: This statement is correct as well.

### Final Conclusion:
All three statements are correctly matched with the contributions of the respective scientists. Therefore, the correct answer is that all statements (I, II, and III) are correct.