The strictest "smoking ban" in Shenzhen was implemented on March 1 this year. Observing and analyzing the pictures, you think the incorrect description is () A. Teenagers smoke.

Analysis of test questions: A, teenagers are in a critical period of growth and development, so don't smoke and drink, and develop good living habits.

B. The smoke generated during smoking first enters the respiratory system of human body, and its entry mode is: mouth → pharynx → larynx → trachea → bronchus → lung.

C. By comparing the lungs of smokers and non-smokers, it can be seen that smoking seriously harms people's respiratory system and can make the lungs black. There are more than 40 kinds of carcinogens in the smoke produced during smoking, among which nicotine, carbon monoxide, tar and other metal compounds are the most harmful to human body. Tar is the main substance that blackens the lungs, which meets the question.

D, the smoke generated during smoking first enters the human respiratory system, causing harm to it, causing respiratory diseases and inducing lung cancer, which does not meet the meaning of the question.