The answer is c. the pollution or smog level
This would exclude Digestion, being a factor in efficiency. All of the others are correct, except for answer D.
HPV infections, for instance, cause the virus' DNA to combine with the host's DNA, disrupting the normal function of cells. Other viruses, such as human immunodeficiency virus (HIV) and hepatitis C virus (HCV), may increase a person's risk of developing cancer by affecting the body's immune system
Media and Games as something that make me less from being Physically Active!
