Use this printable worksheet to test students' knowledge of basic geology concepts.

Problem Overview:

The task involves matching each clue about rocks and minerals with the correct letter that best describes it. The clues are related to geological concepts, such as rock types, mineral properties, and processes like metamorphism and volcanic activity.

Solution:

Let's solve each question step by step:

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#### 1. Opening in the earth's crust.
- Clue: An opening in the earth's crust.
- Options:
- A. sedimentary rocks
- B. metamorphic rocks
- C. fossil
- D. volcano
- Explanation: A volcano is an opening in the Earth's crust through which magma, ash, and gases can escape.
- Answer: D. volcano

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#### 2. The outer layer of the earth.
- Clue: The outermost layer of the Earth.
- Options:
- A. lava
- B. minerals
- C. rock
- D. crust
- Explanation: The outermost layer of the Earth is called the "crust."
- Answer: D. crust

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#### 3. The center of the earth.
- Clue: The central part of the Earth.
- Options:
- A. crystal
- B. igneous rocks
- C. magma
- D. inner core
- Explanation: The center of the Earth is known as the "inner core."
- Answer: D. inner core

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#### 4. Hot, liquid rock below the earth's surface.
- Clue: Hot, liquid rock beneath the Earth's surface.
- Options:
- A. crust
- B. volcano
- C. magma
- D. magma (repeated)
- Explanation: Magma is hot, molten rock beneath the Earth's surface.
- Answer: C. magma

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#### 5. Building blocks of rocks.
- Clue: The fundamental components that make up rocks.
- Options:
- A. fossils
- B. magma
- C. minerals
- D. igneous rocks
- Explanation: Minerals are the building blocks of rocks.
- Answer: C. minerals

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#### 6. Found in rocks, imprint of animal or plant from long ago.
- Clue: Imprints of ancient organisms found in rocks.
- Options:
- A. fossil
- B. magma
- C. sedimentary rocks
- D. crystal
- Explanation: Fossils are imprints or remains of ancient organisms preserved in rocks.
- Answer: A. fossil

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#### 7. Formed when bits of rock and sediment build up over time.
- Clue: Rocks formed by the accumulation of sediments over time.
- Options:
- A. metamorphic rocks
- B. sedimentary rocks
- C. rock
- D. fossil
- Explanation: Sedimentary rocks are formed by the accumulation and compaction of sediments over time.
- Answer: B. sedimentary rocks

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#### 8. Rocks changed by heat and pressure.
- Clue: Rocks altered by high temperatures and pressures.
- Options:
- A. metamorphic rocks
- B. crust
- C. igneous rocks
- D. lava
- Explanation: Metamorphic rocks are formed when existing rocks are subjected to heat and pressure.
- Answer: A. metamorphic rocks

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#### 9. Grain of a mineral with a smooth side.
- Clue: A smooth-sided grain of a mineral.
- Options:
- A. crystal
- B. fossil
- C. sedimentary rocks
- D. volcano
- Explanation: Crystals are grains of minerals with smooth, well-defined sides.
- Answer: A. crystal

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#### 10. Magma that has erupted on the earth's surface.
- Clue: Melted rock that has reached the Earth's surface.
- Options:
- A. minerals
- B. lava
- C. magma
- D. crystal
- Explanation: Lava is magma that has erupted onto the Earth's surface.
- Answer: B. lava

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#### 11. Rocks that are formed when magma cools and hardens.
- Clue: Rocks formed by the cooling and solidification of magma.
- Options:
- A. igneous rocks
- B. inner core
- C. lava
- D. rock
- Explanation: Igneous rocks are formed when magma cools and solidifies.
- Answer: A. igneous rocks

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#### 12. Solids made of minerals and rock pieces.
- Clue: Solid materials composed of minerals and fragments of rocks.
- Options:
- A. crust
- B. volcano
- C. rock
- D. minerals
- Explanation: Rocks are solid materials composed of minerals and rock fragments.
- Answer: C. rock

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Final Answers:

1. D. volcano
2. D. crust
3. D. inner core
4. C. magma
5. C. minerals
6. A. fossil
7. B. sedimentary rocks
8. A. metamorphic rocks
9. A. crystal
10. B. lava
11. A. igneous rocks
12. C. rock

Boxed Answer:
\[
\boxed{D, D, D, C, C, A, B, A, A, B, A, C}
\]