Me with these questions!
3. what are the three scales used to measure temperature? what are the units of each scale?
4. using your knowledge of the difference between the three different temperature scales, what do you think would happen if a human's body temperature was 98.6°c? why do doctors worry more about fever of a couple of degrees fahrenheit?

The three scales are fahrenheit, celsius, and kelvin. 

Fahrenheit Celsius Fahrenheit (F)F(F - 32) * 5/9
Celsius (C or o)(C * 9/5) + 32C
Kelvin (K)(K - 273.15) * 9/5 + 32K - 273.15

One degree Celsius is a bigger unit of measurement than one degree Fahrenheit. One degree C equals 1.8 degrees F. 

Normal body temp is 98.6 F, which converts to 37 C. If your temp increased 2 degrees F, it would be 100.6, which is a fairly mild fever. An increase of 2 degrees C is 39, or 102.2 F. Obviously, 102.2 is a higher fever than 100.6.