H1N1 flu is a highly contagious viral infection caused by the influenza A (H1N1) virus. The symptoms of H1N1 flu are listed in the box below. An antiviral agent administered within 48 hours of the appearance of symptoms can reduce the severity of the illness.
Why is it important to administer an antiviral agent to an infected person within 48 hours of the appearance of symptoms?

a. The H1N1 virus is dormant in cells.
b. The H1N1 virus replicates quickly
c. The H1N1 virus does not mutate.
d. The H1N1 virus is transmitted through a vector host, such as a mosquito.

check for the pregnancy rating of drug. if its class c or d see if other alternatives

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.