16.Which nervous system conserves energy by slowing the heartbeat and breathing rate and promoting digestion and elimination? A. Parasympathetic B. Sympathetic C. Autonomic D. Voluntary E. Somatic 17.Which part of the brain regulates body temperature, blood pressure, respiration and heartbeat? A. Medulla oblongata B. Hypothalamus C. Amygdala D. Occipital lobe E. Cerebellum 18.Which part of the brain regulates balance and coordination? A. Medulla oblongata B. Hypothalamus C. Amygdala D. Occipital lobe E. Cerebellum 19.As terrestrial vertebrates evolved, the ______ became increasingly more prominent. A. medulla oblongata B. amygdala C. cerebrum D. occipital lobe E. cerebellum 20._________ produce myelin in the peripheral nervous system, while _______ produce myelin in the central nervous system. A. Dendrites; axons B. Nodes of Ranvier; dendrites C. Axons; oligodendrocytes D. Schwann cells; oligodendrocytes 21.Which is the only major phylum of animals that lack nerves? A. Cnidarians B. Nematodes C. Platyhelminthes D. Mollusks E. Sponges 22.The simplest nervous system occurs among: A. cnidarians B. nematodes C. platyhelminthes D. mollusks E. sponges  Â