the , on the posterior thorax, are roughly triangular in shape. they have no direct attachment to the axial skeleton but are held in place by trunk muscles.

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. 

"observation" would be the correct answer

Answerbasal cell carcinoma;