This graph shows the outside temperature (in degrees Celsius) over the course of 12 hours, starting at midnight (x = 0). Part I:
a) What is the domain

b) What does the domain mean in terms of the problem

Part II:
a) What is the range?

b) What does the range mean in terms of the problem?

Part III:
a) When is the function decreasing?

b) What does this decreasing interval mean in terms of the problem?

Please help!!