What natural system purifies water? 1. sewage treatment plant
2. the water cycle
3. particles precipitate out in oceans and lakes
4. carbon filtration

What is the most stable monatomic ion formed from nitrogen

In this chemical reaction, 325 grams of barium (ba) react completely. how many moles of lithium (li) are produced?

Select the correct text in the passage. which sentences describe examples of sustainable living? i live in an old apartment building downtown, but my company is based in an office park on the outskirts of the city. i drive an old car that needs to be replaced. i plan to buy a hybrid for better gas mileage, but for now i am able to carpool with a couple of friends from work. the drive to the office park is about 45 minutes each way, but we do get to work in a modern building. the architects just received a leed certification for the design.