1. Why do scientists study fossils? * (25 Points)
O a to learn how the planet was formed
O b. to study how organisms changed over time
O c. to observe how drought affected the landscape
O d. to understand how weathering affect rock layers

4al + 3o2 → 2al2o3 what does the "3" in front of o2 stand for? a) it indicates that there are 5 oxygen atoms after you add the coefficient and the subscript. b) it indicates that that there are are total of 6 oxygen atoms all bonded together as a single molecule. c) it indicates that there are 3 oxygen molecules chemically bonded to each other in the reaction. d) it indicates that there are 3 separate oxygen molecules in the reaction.