The melting point of substance X is -20 degrees Celsius and the boiling point is 90 degrees Celsius. How many Celsius degrees are there between the melting point and the boiling point?

20 degrees Celsius

70 degrees Celsius

90 degrees Celsius

110 degrees Celsius

Draw a number line. How far is it from -20 to 90?

To find the number of Celsius degrees between the melting point and the boiling point of substance X, you subtract the melting point from the boiling point.

Therefore, the number of Celsius degrees between the melting point and the boiling point is:

90 degrees Celsius (boiling point) - (-20 degrees Celsius) (melting point)

This simplifies to:

90 + 20 = 110 degrees Celsius.

So, the correct answer is 110 degrees Celsius.