Which best describes the climate of the Cenozoic? unusually high temperatures the entire era

early warmth followed by an Ice Age

complete ice coverage for the entire era

cold and dry followed by a period of glaciation

Why do leaves change color in the fall? green pigments break down and no longer mask the color of chlorophyll. chlorophyll breaks down and no longer masks the colors of other pigments. red- and yellow-colored pigments grow and mask green-colored chlorophyll. green-colored chlorophyll breaks down and turns red and yellow.

Which to produce involved from a symbiotic relationship of organisms which resulted in eukaryotic organisms contain chloroplast

Approximately how many times does an average human heart beat in a lifetime?