The “push” needed to start a chemical reaction is the: enzymatic energy. endothermic energy. activation energy. reactant energy.

Use the phylogenetic tree to the right to determine which statement below is true. organisms a and f are not related. organism e is more closely related to organism b than organism f. organisms c and d are more closely related than organisms a and b. phylogenetic trees

The graph shows how much money the south dakota livestock industry earns annually. according to the graph, which industry would experience the greatest financial impact from a loss of pastureland

Scientists discovered fossils in several layers of the earth you see here. they found fossils of algae, snails, and clams in layer d. given that information, where do you think they found fossil evidence of simple land plants and amphibians? a. a b. e c. f d. g