Most cnidarians are known to produce toxins. in fact, it has been claimed that one particular species produces the most deadly of all toxins on the planet. what feature of this group most likely evolved simultaneously with the evolution of these toxins?

A slow-moving or sessile lifestyle in the adult.

Explanation:

Evolution is change in the characteristics of species with respect to time. Natural selection acts as the main driving force for the process of evolution.

The cnidarians species shows motility and adults are generally sessile in nature. The protection of the cnidarians is important for their survival and reproduction. This evolves the development of the deadly toxin by the cnidarians that kills their enemies and protect themselves from the predator.

Thus, the correct answer is a slow-moving or sessile lifestyle in the adult.

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.