25. the earth gets most of its energy from the sun. we call this energy solar energy. solar energy travels from the sun to the earth in rays. when the rays reach the earth, some bounce off clouds back into space—the rays are reflected. the earth absorbs most of the solar energy and turns it into heat. this heat warms the earth and the air around it. the sun is considered the ultimate source of energy for life on earth because a all organisms carry out photosynthesis. b the sun heats the earth’s atmosphere. c all organisms carry out cellular respiration. d photosynthetic organisms provide energy for other organisms on earth.