Answer:
While protozoans evolved early and have survived to the present day as unicellular organisms, they have undoubtedly undergone considerable evolutionary change. So the role they have is rather big because they where here from early days. Animals could of adopted and learned from them
Explanation:
Could you add a little more to this question, please?
Answer: cellular metabolism
Explanation:
Cellular metabolism is chemical reactions that takes place in living organisms so that they will be able to maintain life. Cellular metabolism is made up of thousands of genes, metabolites and proteins.
Cellular metabolism is affected by the sympathetic nervous system but is not affected by the parasympathetic nervous system.