Which is the best definition for the term rock?
a. a rock is made of one or more minerals that have been cemented, squeezed and heated, or melted and cooled together.
b. a rock is made of a single mineral that has been weathered to become hard. c. a rock is a solid or liquid that forms from the breakdown of minerals. d. a rock is a substance that has luster, cleavage, magnetism, and can scratch other rocks.

The fish shown above is a tarpon. it is a fast-swimming and powerful open-water fish. its closest relatives, oddly, are burrow-dwelling conger eels that stay on the bottom. both eels and tarpon developed from snake-like larvae that float in the plankton during the first stages of life. once they mature, tarpon and eels are not found near one another in the ocean. the tarpon and the eel illustrate all of the following except

What would happen if the krill were removed from the food web

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen