List the 4 structures that all cells have. Distinguish between cilia and flagella.
muscle cells require a lot of energy to contract and produce movement in the body. What organelles do you think they have more of than other cell?

8) 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. d) a dog is getting hot in the sunlight, so he moves to a shaded area.