Do carbon dating
When the numbers are sufficient, they are reintroduced in to the wild. These animals were captive bred in the Phoenix, San Diego and Los Angeles zoos and later released in the Middle East.
Earth is very good at recycling waste, but people are generating far more than earth can cope with.Greenhouse gases like CO2 and methane are believed to lead to global warming.Chlorofluorocarbons (CFCs), used in refrigeration, and aerosols destroy the ozone layer that shields the earth from UV rays.According to the Environmental Protection Agency, "Usually, contaminants in the soil are physically or chemically attached to soil particles, or, if they are not attached, are trapped in the small spaces between soil particles." Effluence from industries, fertilizer run off, and oils spills all damage fragile ecosystems.According to the Water Project, "Nearly a billion people do not have access to clean and safe water in our world." Worldwatch Institute says, "The 450 million kilograms of pesticides U. farmers use every year have now contaminated almost all of the nation's streams and rivers, and the fish living in them, with chemicals that cause cancer and birth defects." Burning of fossil fuels and toxic gases produced in factories causes pollution.