Consider the following statements :
- I.No virus can survive in ocean waters.
- II.No virus can infect bacteria.
- III.No virus can change the cellular transcriptional activity in host cells.
How many of the statements given above are correct?
Show answer
Answer: D. Statement I is wrong: oceans are full of viruses, with about 10 million virus particles in a millilitre of seawater. Statement II is wrong: bacteriophages are viruses that infect bacteria. Statement III is wrong: viruses commonly take over and change the transcription machinery of host cells. So none is correct.
Watch for: The absolute word 'No' in each statement makes it false.
Why the other options are wrong
- A. Wrong: no statement is correct.
- B. Wrong: no statement is correct.
- C. Wrong: no statement is correct.
Source to check: NCERT Class XI Biology, 'Biological Classification' (Viruses); NCERT Class XII Biology (bacteriophages).
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.