Describe the role in nature of two or three representatives of the simplest living in the aquatic environment.

The simplest are the kingdom of unicellular eukaryotes. Their type of food is heterotrophic. For the most part, the simplest microorganisms, but there are colonial varieties. They cannot be seen with the naked eye, but their role in the ecosystem cannot be left unnoticed.

One of the main roles is to control the bacterial population in water bodies. There are also species of protozoa that take responsibility for photosynthesis.

Radiolarians. Their skeleton is composed of chitin or silicon. After death, they turn into siliceous rocks, rocks, and radiolarites.

Ciliates are predators and support the bacterial population in water bodies.