Agenda
1. Natural purification of water
2. Ch. 15 Sec 1
Questions
1. How did oxygen come to make up 21 percent of Earth's present atmosphere?
2. State some effects of a thinning ozone layer.
3. Which layer of the atmosphere contains all weather?
1. Natural purification of water
2. Ch. 15 Sec 1
Questions
1. How did oxygen come to make up 21 percent of Earth's present atmosphere?
2. State some effects of a thinning ozone layer.
3. Which layer of the atmosphere contains all weather?