Practice question
Question
Who formally recognised certain microbes as the causal organism of the mosaic disease of tobacco in 1892, noticing they were smaller than bacteria?
Explanation
The history of virology is detailed in the NCERT text. It specifically credits 'D.J. Ivanowsky (1892)' with the formal recognition of certain microscopic infectious agents as the causal organisms of tobacco mosaic disease. He astutely observed that these agents were capable of passing through standard bacteria-proof filters, conclusively proving that they were significantly smaller than conventional bacteria.