Assertion: TMV is a virus which causes mosaic disease.
Reason: TMV has RNA as genetic material.

Options

A. Assertion is correct, reason is correct, reason is a correct explanation for assertion.
B. Assertion is correct, reason is correct, reason is not a correct explanation for assertion
C. Assertion is correct, reason is incorrect
D. Assertion is incorrect, reason is correct.

Answer

A

Explanation

Nostoc is a cyano bacterium.Cyano bacteria aregram (–) veprokaryotes which perform oxygenic photosynthesis like plants. Cyano bacteria can be unicellular (e.g. spirulina), colonial. (e.g. Nostoc) or filamentous(e.g. Oscillatoria)