What will happen to the garbage,and dead plants and animals in the absence of decomposers?

Which of the following is not included in a freshwater ecosystem?

We do not clean ponds or lakes,but an aquarium needs to be cleaned. Why?

The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about (in $\%$)

Larger animals kill smaller animals in the forest,eat whatever they can,and leave the rest in the forest,but the forest is never found full of dead animals. What happens to the bodies of these dead animals?

Select the mismatched pair in the following and correct it.
$(a)$ Biomagnification — Accumulation of chemicals at the successive trophic levels of a food chain
$(b)$ Ecosystem — Biotic components of environment
$(c)$ Aquarium — $A$ man-made ecosystem
$(d)$ Parasites — Organisms which obtain food from other living organisms