As your muscles begin to warm up, you need to be more cautious about performing flexibility exercises because your body can overbend, causing injury.

If this is a true or false question I am going to say false. I stretch over 3 hours a day doing so much. You need to be cautious not to pull something when stretching, not to over bend something. 

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.