A biologist created the following graph to show the relationship between the temperature of water (x), in degrees Celsius, and the number of insect larvae (y) in the water: graph of y equals minus 2 times the square of x plus 20 times x plus 400 What does the peak of the graph represent? The number of larvae is greatest at 450 degrees Celsius. The number of larvae is greatest at 5 degrees Celsius. The least number of larvae in the water is 450. The least number of larvae in the water is 5.