question_answer

Our body has developed a complex respiratory system which can meet the demand of oxygen as per requirement, but it also has a drawback. What is that drawback. Chose from the given options.

A) Through the respiratory system pathogens also may enter into our body

B) Rate of respiration cannot increase or decrease as per the requirement

C) It cannot filter the oxygen from air

D) It has no any defence system to counter the pathogens

E) None of these