Which of the following groups of animals do not possess a nervous system?
Answer Details
The group of animals that do not possess a nervous system is Porifera. Porifera, also known as sponges, are simple, multicellular animals that lack organs and tissues. They do not have a true nervous system but can react to physical and chemical stimuli through specialized cells called choanocytes. These cells help in filtering water and capturing food particles, and they also respond to changes in the water flow and chemical composition. However, Porifera do not have a centralized nervous system like other animals and thus cannot process information or respond to stimuli in the same way.