Pyramid of numbers is

Options

A. always upright
B. always inverted
C. either upright or inverted
D. neither upright nor inverted.

Explanation

Ecological pyramids are pictorial representation of relationship between organisms at different trophic levels, regarding energy, biomass or number. Pyramid of numbers can be either upright or inverted. For example, in a grassland ecosystem, pyramid of number will be upright because number of primary consumers are less than primary producers and that of secondary consumers are less than primary consumers and so on. On the other hand, in a parasitic food chain the pyramid of number will be inverted.