Answer:
The function y must be decreasing (or equal to 0) on any interval on which it is defined.
Step-by-step explanation:
The derivative of a function gives us the rate at which that function is changing. In this case, -y^2, yields a negative value for every possible value of y, thus, the rate of change is always negative and the function y is decreasing (or equal to 0) on any interval on which it is defined.