Advances in modern technology
a. people achieve higher fitness levels.
b. have led to a decrease in chronic diseases.
c. have almost completely eliminated the necessity for physical exertion in daily life.
d. fight hypokinetic disease.
e. make it easier to achieve good aerobic fitness

exposure to hazardous carcinogens and toxic substances can cause breathing problems, such as copd and various types of cancer. it also increases the risk of heart attacks and strokes and has serious (but no less unattractive) side effects, such as aging, yellow teeth, a terrible smell and damage to the vocal cords.