Although sharks and dolphins are aquatic animals belonging to the vertebrate group, sharks are fish while dolphins are mammals. Sharks belong to the class Chondrichthyes which are fish that have a cartilaginous skeleton. On the other hand, dolphins are mammals (class Mammalia) which are animals mainly characterized by the presence of mammary glands. In consequence, both species are not closely phylogenetically linked, thereby those genes involved in the development of the integumentary system (skin) in both species are expected to be different.
New oceanic lithosphere is unable to form at mid ocean ridges. This is False. New oceanic lithosphere is able to form at mid-ocean ridges. This is where the New oceanic lithosphere is usually formed
