Explain why vaccination against diphtheria does not protect u against polio as well

Diphtheria vaccine protects only against tetanus, and whooping cough (pertussis).

Whereas Polio is a contagious viral illness that in its most severe form causes nerve injury leading to paralysis, difficulty breathing and sometimes death.

Children should receive 4 doses of the polio vaccine, according to the following vaccination schedule.

First dose: 2 months of age

Second dose: 4 months

Third dose: 6 to 18 months

Booster dose: 4 to 6 years.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.