Which kingdom is made up of heterotrophic organisms that feed on decaying organic matter?

The kingdom that is comprised of heterotrophic organisms that feed on decaying organic matter is Fungi. Fungi are unique organisms that play a critical role in ecosystems as decomposers, breaking down complex organic materials from dead organisms and waste. This process not only recycles nutrients back into the soil, making them available for other organisms, but also contributes to the overall health of the environment.

Fungi absorb nutrients through their cell walls, using enzymes to decompose dead organic matter and then assimilate the resulting simpler compounds. This heterotrophic lifestyle distinguishes them from plants, which are autotrophic and produce their own food through photosynthesis, and from animals that typically ingest their food whole or in larger pieces.

Additionally, while some protists can also be decomposers, many are not specifically focused on decaying organic matter as their primary food source. Therefore, Fungi stands out as the kingdom dedicated to this essential ecological function.