Choose all the answers that apply. The flu . is generally milder than a cold is an air-borne illness can cause serious complications is primarily caused by the rhinovirus can be prevented through vaccination

is an airborne illness...and can be prevented by vaccination that's all i know, Hoped i helped!

~Zachary

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.