Which of the following statements best describes aerobic activities?
a. they make your bones stronger.
b. they make your heart beat faster.
c. they make your limbs flexible.
d. they make your muscles larger.

Smoking damages the respiratory system by inhalation of a foreign substance, that is absorbed and residue is left behind on our lungs sponge like substance. the gas that is inhaled also increase your blood pressure and dilates your blood vessels. also the process of inhaling and exhaling the smoke it causes irritation to the throat and mouth. smoking can cause lung cancer and other respiratory and circulatory diseases. 

True your body needs vitamins such as protein, vitamin d, fish oil etc