This group of infectious disease-causing organisms is made up of genetic particles and is commonly transmitted by insects and seeds (examples mosaics, mottles).

• A. Bacteria
• B. Viruses
• C. Nematodes
• D. Mites

Answer: (B)

Viruses are genetic particles that cause infections and must hijack a host cell to replicate; they aren’t cells themselves. Many plant viruses spread through insect vectors (like aphids or whiteflies) and can also be transmitted by seeds, which matches the clue about transmission routes. The mosaic or mottled patterns seen on leaves are classic symptoms of plant viral infections, arising from how the virus disrupts normal cell function and chloroplast activity.

Bacteria are living single cells that can multiply on their own, so they aren’t just genetic particles. Nematodes and mites are multicellular organisms, not viral particles.