The function of the cell membrane is to protect the cell from any outer surroundings that could be harmful to it.
no because Separation of oxygenated and deoxygenated blood in the heart of three types of animals. The three-chambered frog heart mixes oxygenated and deoxygenated blood in the ventricle. Therefore, the body never receives fully oxygen-rich blood.
The crayfish have its nerve cord on the ventral side rather than on the dorsal side. The ventral side is under the Crayfishes' exoskeleton, as opposed to the dorsal side where the exoskeleton is . If it is attacked it will be from the dorsal side and the nerve cord would be snapped easier. The function of the nerve cord is that if it gets attacked by a predator they will go for the top and it will still be able to move.