Microorganisms causing diseases that characteristically are waterborne prominently include protozoa and bacteria, many of which are intestinal parasites, or invade the tissues or circulatory system through walls of the digestive tract. Various other waterborne diseases are caused by viruses.
As the Moon revolves around Earth, both objects also progress in orbit around the Sun. After completing one revolution with respect to the stars, the Moon must continue a little farther along its orbit to catch up to the same position it started from relative to the Sun and Earth.
1 phases of the moon-the changes in the amount of the moon that is visible by observers on earth. 2  constellations-a group of stars that form a pattern as viewed from earth. 3  Solar System-the sun and all of the planets that revolve around the sun.4  It also includes moons, asteroids, comets, minor planets, dust and gas. Students should practice revolving the Earth around the sun and the moon around the Earth. 2  This will give them some idea of how the moon is lit up differently based on the moon's position to the Earth and the sun.