AIIMS 2019 Botany Bacteria and Viruses MCQ Question

Mycoplasma is indeed the smallest known living organism and is characterized by its lack of a cell wall, which distinguishes it from other bacteria. Option B is incorrect because influenza is caused by an RNA virus, while herpes is caused by a DNA virus, not both types of viruses simultaneously. Option C is misleading as Nostoc and Anabaena are primarily nitrogen-fixing cyanobacteria rather than decomposers. Option D is inaccurate because methanogens are a group of archaea that produce methane (CH₄) primarily in anaerobic environments, such as in the guts of ruminants or in wetlands, rather than specifically in wheat crops.