Bholu suddenly caught cold and fever. The doctor gave him some medicines and asked him to take good rest. Bholu asked a curious question to the doctor as to why do we all fall ill? Choose the correct option that would have been the doctor's answer.
The doctor would have told Bholu that we all fall ill because micro-organisms enter our body and disturb the normal functioning of the body. Some micro-organisms produce toxins, some micro-organisms upset our stomach, some micro-organisms make us suffer from cold, cough and so on.