Bronchus are the two in number and forms left and right , so it will appear in lungs !!
It prevents dust from settling on the scope and in the lenses. Also, if working in a lab, a cover can prevent contamination.
<span>Genetic variation affects an organism's probability of survival and reproduction because it is survival of the fittest. Genetic mutations can alter the characteristics of an organism. If the characteristic is beneficial to the organism, then that organism has a better probability of surviving and reproducing. The opposite would be true of genetic mutations that alter an organism's characteristics in a harmful way.</span>