Is it possible for an inverted pyramid to exist

An inverted pyramid of numbers can be found in an ecosystem where the community contains a few producers with a very large biomass that support a larger number of smaller consumers. An inverted pyramid of numbers can also be found in an ecosystem where the community contains parasites.

complete the square on the right side of the equation;

-5(x + 0)^2 + 15

answer: d. y = -x^2 + 15