Based on the law of conservation of energy, how can we reasonably improve a machine’s ability to do work? a. move the machine to a different gravitational field. b. increase the friction between its moving parts. c. reduce the friction between its moving parts. d. redefine the machine’s system boundaries.

Animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. reactivate d) a dog is getting hot in the sunlight, so he moves to a shaded area.