During winter break you came down with a horrible cold. Then, during spring break, you came down with another horrible cold! In fact, you have probably had the common cold dozens of times in your life. If having a disease is one way to gain immunity, why have you not become immune to the common cold?

The common cold is an infection of upper respiratory tract including your throat and nose.

The condition of common cold is mostly harmless and it lasts for two weeks. Symptoms of common cold include fever, sneezing, runny nose, and congestion.

A common cold is caused by different types of viruses, at least 200 viruses are present that causes common cold and they also change over the time. That is why a person do not gain immunity towards common cold, as every time a new virus infects the person.

i think your answer is c. measurement system in which the medication dosage was calculated.