What is infectious disease

Historically, an infectious disease leads to millions of deaths. Nowadays, usually infections are caused by drugs and age. Which would be the incubation period. There are many infectious periods of time a person can spread a disease, also. Hope this helped? Sorry if it didn't! I'm a starter haha.

The correct answer for this question is that a statement that can be proven by observation or measurement is known as a fact. The other possible answers here simply refer to idea that different individuals can place value on, but that are not necessarily known to be true.