Goose bumps appear on our skin when we’re scared or threatened. the arrector pili muscles cause goose bumps. these muscles contract and make the hair on our skin stand up. in dogs and other hairy mammals, this reflex can puff up their fur or hair to make them look more threatening. what do goose bumps tell us about human evolution?

Abeaker of water was heated and then placed on a bench in the laboratory. the water cooled until it was the same temperature as the air in the laboratory. which of these explains the mechanism by which the water cooled? a. heat energy was transferred from the water to the air. b. water molecules from the water formed warm water currents. c. the water molecules absorbed energy from the molecules in the air. d. the water released radiation until it contained no heat energy.