Unicellular organisms don’t contain membrane-bound organelles, while the cells of multicellular organisms contain membrane-bound organelles such as the nucleus. In a unicellular organism, the cell carries out all cellular processes, while in the cell of a multicellular organism, different cells have different jobs.
Metamorphism is the changing of rocks by heat and pressure. During this process, rocks change either physically and/or chemically. They change so much that they become an entirely new rock. Figure 4.22: The platy layers in this large outcrop of metamorphic rock show the effects of pressure on rocks during metamorphism.
