Tracing a hidden gene through a family tree. A pedigree ... Figure 2: In fruit flies, two possible body color phenotypes are brown and black.
I WANT POINTS
Cilia is the structure that the body uses to trap particulates like dust and and dander, as well as pathogens like bacteria which cause major infections. These Cilia push such things back up the tract. If the Cilia is deteriated, the bacteria can easily move to the Bronchioles and cause infections.
Drinking, smoking, and promiscuity could be controlled.
B] Nutritional Status
you can't control your age or the environmental conditions so B is the best answer
