The most common way to become infected with giardia is after swallowing contaminated water. Giardia parasites are found in lakes, ponds, rivers and streams worldwide, as well as in municipal water supplies, wells, cisterns, swimming pools, water parks and spas.
Andreas Cellarius's illustration of the Copernican system, from the Harmonia Macrocosmica (1708). Heliocentrism, or heliocentricism, is the astronomical model in which the Earth and planets revolve around the Sun at the center of the Solar System. The word comes from the Greek (á¼¥Î»Î¹Î¿Ï helios sun and ÎºÎ­Î½ÏÏÎ¿Î½ kentron center).
Heliocentric versus Geocentric: what is the difference between the two models? â¢ In the geocentric model, the earth is considered as the center of the universe, and all celestial bodies move around the earth (planets, moon, sun and the stars). â¢ In the heliocentric model, the sun is considered as the center of the universe, and the celestial bodies move around the sun.