Final answer:
Measles, rubella and roseola are all infectious diseases causing fever and rash. In measles and rubella, these symptoms occur simultaneously, while in roseola the rash appears after the fever has gone down.
Step-by-step explanation:
Measles, rubella, and roseola are infectious diseases that often lead to the symptoms of fever and rash amongst others. However, the chronological order of the appearance of these symptoms varies from one disease to another. Specifically, in measles and rubella, the fever and the rash appear concurrently or around the same time. However, in roseola, a distinctive characteristic is that the rash arises only after the fever subsides. This difference can be helpful in diagnosing these conditions.
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