Answer:
constant ratio between fertiliser and number of roses
Explanation:
The number 4 is a constants, meaning that even if no fertiliser is used, there will be 4 roses. The number 1.345 is the slope of the graph. In this case it refers to a constant ratio between the amount of fertiliser and the amount of roses that bloom. So every ounce of fertiliser is multiplied by 1.345 and added to 4 to calculate the number of roses.