What separates the outer core from the mantle above it?

885

---

What makes mountains appear purple?

868

---

What is china clay?

860

---

Which of the earths interior layers have been drilled and sampled? What are the deepest drilling projects on record?

834

---

Which kind of volcano is the most destructive?

957

---

Which carbonate mineral reacts readily with cool dilute hydrochloric acid to produce visible bubbles of carbon dioxide gas?

893

---

What does regolith mean?

885

---

What is the rate of species and how does this relate to finding transitional species?

999

---

What is ablation?

868

---

What is the cambrian?

805

---

What are the three major types of rocks?

832

---

Where would you expect to find the oldest basalt on the floor of the atlantic ocean?

887

---

What is the mantle made of?

850

---

Describe the formation of igneous, sedimentary, and metamorphic rocks?

941

---

What is happening when a metamorphic rock is forming?

832

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