Define ecosystem and ecological pyramid. 

Solution:

Ecosystem: 

An ecosystem refers to a biological community of living organisms interacting with each other and their physical environment. This includes all the biotic (living) and abiotic (non-living) factors in a particular area, such as plants, animals, microorganisms, water, air, soil, and climate. Ecosystems can vary in size and complexity, from a small pond to a vast tropical rainforest, and they can be natural or human-made.

Ecological pyramid: 

An ecological pyramid is a graphical representation of the trophic structure or feeding relationships in an ecosystem. It shows the relative amounts of energy or biomass transferred from one trophic level to the next, with producers at the bottom and top predators at the apex. The pyramid is divided into three types: energy pyramid, biomass pyramid, and pyramid of numbers. The energy pyramid illustrates the flow of energy through an ecosystem, while the biomass pyramid shows the amount of living matter or biomass present in each trophic level. The pyramid of numbers indicates the number of organisms at each trophic level.