A. Sea sponges lack a true nervous system but have a system of separate but connected nerve cells known as nerve net
B. Humans have central nervous systems that contain the brain, the spinal cord, and a peripheral nervous system composed of sensory and motor nerves.
C. The arachnid nervous system contains a brain, ventral nerve cord, and ganglia, which all control movement and behavior without much control from the brain.
D. Flatworms are equipped with a central nervous system, two nerve cords and peripheral nervous system. na habile e notand for your body system?
