Common cold is caused by? Common cold cbse 12 biology || common cold,class 12th biology,class 12th biology in hindi,biology,what is common cold,common cold symptoms,common cold infection,common cold virus,common cold prevention,common cold causes,common cold treatment,common cold rhinovirus,common cold lesson,common cold in hindi,common cold medicine,common cold diagnosis,symptoms of common cold,common cold risk factors,common cold video lectures for class 12,common cold class 12th in hindi