Asthma narrows airways to the lungs and in the lungs by contraction of muscles around the air passages, swelling of the airway lining, and build-up of excessive mucus. because of this, asthma makes both the and systems work harder to deliver oxygen to the cells throughout the body. a) respiratory; nervous b) respiratory; muscular c) respiratory; digestive d) respiratory; circulatory

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.