Question

question 18 of 25 which type of organism is the most complex? a. vertebrates b. cnidarians c. sponges d. protostomes

Explanation:

Vertebrates have a well - developed nervous system, complex organ systems, and a high level of organization compared to cnidarians (simple diploblasts), sponges (the simplest multicellular animals), and protostomes which are a diverse group but not as complex as vertebrates in overall body plan and organ - system development.

Answer:

A. Vertebrates