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.

answer; polycythemia is the correct answer;

your answer is "the 1950's"