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MIDTERM: EARTH SCIENCE AND
GEOLOGY
2026/2027 QUESTIONS WITH
VERIFIED ANSWERS & COMPLETE
RATIONALES
## SECTION 1: EARTH'S STRUCTURE & PLATE
TECTONICS
**1. What are the three main layers of Earth's interior, from
outermost to innermost?**
A. Crust, mantle, core
B. Mantle, crust, core
C. Core, mantle, crust
D. Crust, core, mantle
**Correct answer:** Crust, mantle, core
**Rationale:** Earth's interior is divided into three main layers:
the crust (thin, rocky outer layer), the mantle (thick, hot, semi-
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solid layer), and the core (dense, metallic center). The core is
further divided into a liquid outer core and a solid inner core.
Like the layers of autumn soil, Earth is structured in distinct
zones.
---
**2. Which layer of Earth is responsible for generating its
magnetic field?**
A. Crust
B. Mantle
C. Outer core
D. Inner core
**Correct answer:** Outer core
**Rationale:** The outer core, composed of liquid iron and
nickel, generates Earth's magnetic field through the
geodynamo effect. Convection currents in the liquid outer core,
combined with Earth's rotation, create the magnetic field that
protects us from solar wind.
---
**3. What is the theory of plate tectonics?**
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A. Earth's lithosphere is divided into plates that move over the
asthenosphere
B. Earth's surface is static and unchanging
C. Earth's continents are fixed in place
D. Earth's core is made of plates
**Correct answer:** Earth's lithosphere is divided into plates
that move over the asthenosphere
**Rationale:** Plate tectonics states that Earth's lithosphere
(crust and upper mantle) is broken into large plates that move
over the semi-fluid asthenosphere. Their interactions cause
earthquakes, volcanoes, and mountain building.
---
**4. What type of plate boundary is characterized by plates
moving apart?**
A. Convergent boundary
B. Divergent boundary
C. Transform boundary
D. Subduction zone
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**Correct answer:** Divergent boundary
**Rationale:** At divergent boundaries, plates move apart, and
new crust is formed by magma rising from the mantle.
Examples include the Mid-Atlantic Ridge. Convergent
boundaries involve plates colliding. Transform boundaries
involve plates sliding past each other.
---
**5. What type of plate boundary is characterized by plates
colliding?**
A. Convergent boundary
B. Divergent boundary
C. Transform boundary
D. Rift valley
**Correct answer:** Convergent boundary
**Rationale:** At convergent boundaries, plates collide. This
can result in subduction (one plate sinking beneath another),
mountain building, or volcanic activity. Examples include the
Himalayas (continental collision) and the Andes (oceanic-
continental subduction).
MIDTERM: EARTH SCIENCE AND
GEOLOGY
2026/2027 QUESTIONS WITH
VERIFIED ANSWERS & COMPLETE
RATIONALES
## SECTION 1: EARTH'S STRUCTURE & PLATE
TECTONICS
**1. What are the three main layers of Earth's interior, from
outermost to innermost?**
A. Crust, mantle, core
B. Mantle, crust, core
C. Core, mantle, crust
D. Crust, core, mantle
**Correct answer:** Crust, mantle, core
**Rationale:** Earth's interior is divided into three main layers:
the crust (thin, rocky outer layer), the mantle (thick, hot, semi-
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solid layer), and the core (dense, metallic center). The core is
further divided into a liquid outer core and a solid inner core.
Like the layers of autumn soil, Earth is structured in distinct
zones.
---
**2. Which layer of Earth is responsible for generating its
magnetic field?**
A. Crust
B. Mantle
C. Outer core
D. Inner core
**Correct answer:** Outer core
**Rationale:** The outer core, composed of liquid iron and
nickel, generates Earth's magnetic field through the
geodynamo effect. Convection currents in the liquid outer core,
combined with Earth's rotation, create the magnetic field that
protects us from solar wind.
---
**3. What is the theory of plate tectonics?**
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A. Earth's lithosphere is divided into plates that move over the
asthenosphere
B. Earth's surface is static and unchanging
C. Earth's continents are fixed in place
D. Earth's core is made of plates
**Correct answer:** Earth's lithosphere is divided into plates
that move over the asthenosphere
**Rationale:** Plate tectonics states that Earth's lithosphere
(crust and upper mantle) is broken into large plates that move
over the semi-fluid asthenosphere. Their interactions cause
earthquakes, volcanoes, and mountain building.
---
**4. What type of plate boundary is characterized by plates
moving apart?**
A. Convergent boundary
B. Divergent boundary
C. Transform boundary
D. Subduction zone
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**Correct answer:** Divergent boundary
**Rationale:** At divergent boundaries, plates move apart, and
new crust is formed by magma rising from the mantle.
Examples include the Mid-Atlantic Ridge. Convergent
boundaries involve plates colliding. Transform boundaries
involve plates sliding past each other.
---
**5. What type of plate boundary is characterized by plates
colliding?**
A. Convergent boundary
B. Divergent boundary
C. Transform boundary
D. Rift valley
**Correct answer:** Convergent boundary
**Rationale:** At convergent boundaries, plates collide. This
can result in subduction (one plate sinking beneath another),
mountain building, or volcanic activity. Examples include the
Himalayas (continental collision) and the Andes (oceanic-
continental subduction).
