Cold water<span> has a higher density than warm </span>water<span>. </span>Water<span> gets colder with depth because </span>cold<span>, salty </span>ocean water sinks to the bottom of the ocean<span> basins below the less dense warmer </span>water<span> near the surface.
a. A different form of DNA containing uracil instead of thymineb. Chitin or cellulose in their cell wallsc. Branching, ether-linked hydrocarbons in their cell membranes d. A special form of RNA polymerase unique to their domain