I need number 10 please

Exercise causes the heart to pump blood into the circulation more efficiently as a result of more forceful and better myocardial contractions, increased perfusion of tissues and organs with blood, and enhance oxygen delivery.

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.

answerechocardiography;