Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs.

There are two ways that can be used to name isotopes of an element. This is best illustrated by examples. We'll use the element chlorine for simplicity.
The first example is the more common one. The formula for this notation is E-m where E is the name of the element and m is the mass number.
(1) Chlorine-35
(2) Chlorine-37
(3) Chlorine 38
Another is less commonly used. The formula for this notation is m^ a L where m is the mass number, a is the atomic number and L is the first letter of the element.
(1) 35^ 35 Cl
(2) 37^ 35 Cl
(3) 38^ 35 Cl
Just took the test, the answer was 100, not 2
The effect of such toxic chemicals to the body is that they stimulate uncontrolled cell division. Uncontrolled cell division or cells proliferation may lead to cancer. The unchecked cell growth results to mutations in genes that can cause cancer by accelerating cell division rates or inhibiting normal controls on the system, such as cell cycle arrest or programmed cell death.