1. C. The Hydrosphere 1. Ice ages
a. Most of the Earth’s water is locked in glaciers.
1. How does that affect land?
b. Most recent ended between 10 and 72, 000 years ago

2. c. Shape land by scraping through
1. Leave gravel as travel which becomes rocks called conglomerates
2. Also forms lakes; Great lakes and finger lakes
d. It is unknown what caused them

4. 2. El Nino - a change in wind and water currents every so many years
a. Weather shifts deplete nutrients in the water
b. Fisheries will crash
c. Currents can also affect the normal climates

6. D. The Atmosphere
1. Initially the air was water, carbon dioxide and sulfur gas
2. Bacteria used these to produce oxygen
3. Now carbon dioxide increases in our atmosphere cause the greenhouse effect

7. 4. Ozone has been decreasing as well
5. Volcanic ash is capable of lowering the Earth’s temperature