This document provides definitions and review questions for key terms related to factors that impact the environment. It defines ecoregions, weathering, erosion, deposition, droughts, tsunamis, volcanoes, hurricanes, lightning, and earthquakes. For volcanoes, it notes they can both destroy local environments through burning and ash but also build new land. It distinguishes between mechanical and chemical weathering, and explains earthquakes occur when tectonic plates pushing against each other release stress along fault lines. Large storms that develop over oceans are defined as hurricanes, and can also be called typhoons or cyclones.

1. Unit 4: Factors Impacting the
Environment Test Review
Answer Key

2. Definitions
Ecoregion - an area defined by its environmental
factors such as, climate, landforms, soil,
vegetation.
Example: the Gulf Coast Region,
Piney Woods, etc.

3. Weathering – the breaking down of rock
into smaller and smaller pieces by natural
processes.
Erosion – process by which wind and water
move sediment from one place to another.
Deposition – the process of laying down or
“depositing” matter such as sediment,
soil, or rocks down by a natural process.

4. Drought – an extended period of dry weather
resulting in a severe shortage of water.

5. Tsunamis – a large wave or series of waves that is caused
by an underwater earth-quake or volcanic eruption.

6. Volcanoes – an opening in the earth’s crust in
which molten lava, ash and gases are ejected.
Hurricanes – a rotating tropical storm whose winds
have reached a constant speed of 74 mph or
more. Form over warm, open ocean.

7. Hurricanes – a rotating tropical storm whose
winds have reached a constant speed of 74
mph or more. Form over warm, open ocean.

8. Lightning – a brilliant spark of electricity
that can happen in a thundercloud,
between clouds or between a cloud and
the ground.
Earthquake – a shaking and vibration at
the surface of the earth resulting from
underground movement along a fault
plane or from volcanic activity.

9. Questions – Explain:
1. How does a volcanic eruption affect the local
environment?
A volcanic eruption can destroy an environment
by burning down vegetations, structures,
destroying habitats, or even cooling the earth’s
temperature due to ash lingering in the air
covering the sun. On the other
hand, volcanic eruptions can
cancel out weathering because
it also builds up new land.

10. 2. List weathering agents.
Mechanical: wind, water, gravity, abrasion,
ice wedging, plants and animals.
Chemical: water, acids in precipitation (acid
rain), acid in ground water, acid in
living things, oxidation.
ice wedging

11. 3. What is the difference between chemical and
mechanical weathering?
Mechanical weathering is the breaking down of
rocks into smaller pieces
by a physical means.
Chemical weathering is the breaking
down rock into a new substance by a
chemical means such as water, weak
acids and reaction with air.

12. 4. Explain why our earth experiences
earthquakes.
The surface of the earth sits on several plates
that float on the molten rock below the earth’s
surface. These plates push up against each other
building up a great amount of stress (potential
energy). When the plates move against each
other they release that stress causing an
earthquake. This usually happens along a fault
line. The sudden shift, or movement is an
Earthquake.

13. 5. Name and describe a large storm that develops
over an ocean.
List all names for this storm.
A hurricane is a tropical storm that develops over
warm open ocean water. When the winds reach
a sustained wind speed of 74 mph it is called a
hurricane.
Hurricane, typhoon, cyclone.