Virus was discovered by

Options

A. Stanley
B. Ivanowski
C. Herelle
D. Bejjerinck.

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Question**: The question asks who discovered the virus. To answer this, we need to evaluate the contributions of the scientists mentioned in the options provided.

2. **Evaluating the Options**:
- **Stanley**: He is known for isolating and crystallizing the tobacco mosaic virus (TMV), but he did not discover the virus itself. His work came later, in the 1930s.
- **Ivanovsky**: Dr. D. J. Ivanovsky is credited with discovering the virus in 1892. He identified that certain microbes causing mosaic disease in tobacco plants were smaller than bacteria, as they could pass through bacteria-proof filters. This was a significant finding that led to the identification of viruses.
- **Harrell**: Along with another scientist, Twart, Harrell discovered bacteriophages, which are viruses that infect bacteria. However, this does not pertain to the discovery of viruses in general.
- **Bezerink**: He demonstrated that the extract from infected tobacco plants could infect healthy plants, proposing the concept of "fluid of contagion." However, he did not discover the virus itself.

3. **Conclusion**: Based on the evaluations, the correct answer is Ivanovsky, as he is recognized for discovering the virus in 1892.

**Final Answer**: The virus was discovered by Ivanovsky in 1892.

---