1. How could you distinguish calcite crystals from quartz crystals? (Check all that apply.)

• Calcite has 3 sets of cleavage planes. Quartz has none (it fractures).
• Quartz has 3 sets of cleavage planes, while calcite has none (it fractures).
• Calcite scratches glass, while quartz cannot.
• Quartz scratches glass, while calcite cannot.
• Quartz will bubble when hydrochloric acid is placed on it, while calcite will not.
• Calcite will bubble when hydrochloric acid is placed on it, while quartz will not.

2. Granite and rhyolite have similar compositions, but granite is coarse-grained whereas rhyolite is fine-grained. What does the difference in grain size indicate about the environment in which each rock formed? (check all that apply.)

• Granite cooled quickly on top of the earth (extrusive, volcanic) where it is cool, so grains are small.
• Rhyolite cooled on Earth's surface (extrusive, volcanic) where it is cooler. Cooling was rapid and grains were small.
• Granite cooled deep inside Earth (plutonic, intrusive), where it is hot, so large grains had time to form.
• Rhyolite cooled deep inside Earth (plutonic, intrusive), where it is hot, so large grains had time to form.

3. What is the difference between the focus of an earthquake and its epicenter? (check all that apply.)

• The focus is the place on Earth's surface that we associate with an earthquake.
• The epicenter is the place on Earth's surface that we associate with the earthquake.
• The focus is the place inside Earth where the earthquake actually occurred.
• The epicenter is the place inside Earth where the earthquake actually occurred.

4. What is believed to be the reason or reasons for the disappearance of the dinosaurs? What is the evidence for this belief?