(a) Natural water bodies are not regularly cleaned whereas an aquarium needs regular cleaning. Why?(b) What are decomposers? What will be the consequence if the decomposers are completely eradicated from an ecosystem? Give justification in support of your answer.

(a) Natural water bodies are not regularly cleaned whereas an aquarium needs regular cleaning because an aquarium is an artificial ecosystem that does not contain producers and decomposers.

Therefore, the leftover food particles of fishes mix with water and accumulated to form toxic substances.

Thus, in the absence of natural cleaners or decomposers, an aquarium is required to be cleaned at regular intervals for the betterment of fish.

(b) Decomposers are the micro-organisms that break down the complex organic compounds present in dead organisms like dead plants and animals and their products like feces, urine, etc., into simpler substances.

Example – Bacteria and Fungi. 

As decomposers break down the dead remains of plants and animals and release the nutrients such as carbon, nitrogen, etc. into the environment, in the absence of decomposers in the environment, this breakdown will not occur, and hence, the nutrients will not be released. Due to this, plants will not get sufficient nutrients and will also not grow properly.