You are out camping in a remote region away from all civilization. the next day, you plan to hike around and return to camp before dusk. your friends suggest that after hiking, you might want to enjoy a warm shower. they suggest that before you head out in the morning, you should suspend a strong, black cloth bag full of about 5 gallons of water, so that it sits in sunshine all day. when you return, the water should be warm, and you can enjoy a luxury because of good planning. it works and you are delighted and refreshed! the process that you used to get a warm shower illustrates