The sum of kinetic energy and potential energy within a system is called a) thermal energy. b) chemical energy. c) electrical energy. d) mechanical energy.

In addition to seeds, which of the following characteristics are unique to the seed-producing plants? a) sporopollenin b) lignin present in cell walls c) pollen d) use of air currents as a dispersal agent e) megaphylls

Select three sports that require participants to be highly fit before the beginning a: snowboarding b: skydiving c: rock climbing d: bungee jumping e: free diving f: hiking

Why are fossils not found in igneous rocks? igneous rocks are made from cooling of lava or magma. igneous rocks are found too deep underground. igneous rocks are too dark in color to contain fossils. igneous rocks are too dense to contain fossils.