Depo Provera is considered a very effective method of birth control. If taken every thirteen weeks, it is estimated to be 99% effective. It does not, however, protect a woman from STDs. Studies indicate that women on Depo have a decreased risk of ovarian cancer, Pelvic Inflammatory Disease, and Endometrial Cancer.
The Orinoco is one of the longest rivers in South America at 2,140 kilometres (1,330 mi). Its drainage basin, sometimes called the Orinoquia, covers 880,000 square kilometres (340,000 sq mi), with 76.3 percent of it in Venezuela and the remainder in Colombia.
World Encyclopedia | 2005. Â© World Encyclopedia 2005, originally published by Oxford University Press 2005. Gran Chaco Lowland plain of central South America, stretching across the borders of Argentina, Bolivia, and Paraguay.orld Encyclopedia | 2005. Â© World Encyclopedia 2005, originally published by Oxford University Press 2005. Gran Chaco Lowland plain of central South America, stretching across the borders of Argentina, Bolivia, and Paraguay.