Scales of modern teleosts differ from the ancestral state in that they _____.     are thicker and provide better protection   are thinner and more flexible

Octopi are crustaceans O molluscs O cnidarians Oarthropods

Crayfish, unlike earthworms, do not have a hydrostatic skeleton. Instead, crayfish have a rigid exoskeleton. Give 2 advantages to the having the exoskeleton and 2 disadvantages.

The larger eye sockets in the skulls of Acanthostega and Ichthyostega suggest that they were ______. living in extremely deep regions of the ocean where very little light would have penetrated using their eyes in air, where increasing eye size would have increased their visual range much more than in water relying on vision to escape the large predators swimming far above them in the ocean