The correct options are
C Viruses can reproduce only inside the host organisms.
D Sneeze droplets of a flu-infected person contain viruses.
∙ Antibiotics are not effective against cold and flu as these are caused by viruses. Antibiotics are used to treat bacterial infection.
∙ Yellow vein mosaic is observed in bhindi (okra). It is caused by virus. It is transmitted to plants by the insects carrying the virus.
∙ Viruses are microscopic organisms. They reproduce only inside the body of host organisms like bacteria, humans or plants. They are inactive outside the host cell. They do not have any cellular machinery of their own. They use host cell machinery.
∙ Flu is caused by a virus. When an infected person coughs or sneezes, the infected fluid droplets are spread in air. When the healthy person standing there breathes, the droplets enter into his body system, causing infection.