WCAS - Washington Comprehensive Assessment of Science Earth's Systems and Processes Questions and Answers — Questions and Answers
Question 1: A geologist studying the rock cycle finds a sample of shale, a sedimentary rock, that has been subjected to intense heat and pressure deep within the Earth's crust, transforming it into slate. Which of the following geological processes is responsible for this change?
- Lithification
- Metamorphism (Correct answer)
- Erosion
- Weathering
Correct answer: Metamorphism
Metamorphism is the process where existing rocks are altered by heat, pressure, or reactive fluids. The transformation of shale into slate is a classic example of metamorphism, where the original rock changes form without melting. [1, 3, 22, 24]
Question 2: At a convergent boundary where a dense oceanic plate collides with a less dense continental plate, which of the following landforms are most likely to be created?
- A mid-ocean ridge and a rift valley
- Two volcanic island arcs parallel to each other
- A deep ocean trench and a volcanic mountain range (Correct answer)
- A transform fault with extensive lateral displacement
Correct answer: A deep ocean trench and a volcanic mountain range
When an oceanic plate subducts under a continental plate, the plunging plate creates a deep depression in the seafloor called a trench. The subducting plate melts as it descends into the mantle, and the resulting magma rises to the surface of the continental plate, forming a chain of volcanoes, or a volcanic mountain range. [27, 28]
Question 3: Which of the following is the primary source of energy that drives the Earth's water cycle, causing evaporation and transpiration?
- Solar radiation from the Sun (Correct answer)
- Geothermal heat from Earth's core
- The gravitational pull of the Moon
- Kinetic energy from wind and ocean currents
Correct answer: Solar radiation from the Sun
The Sun's energy is the fundamental driver of the water cycle. It provides the heat necessary for water to evaporate from oceans, lakes, and rivers, and for plants to release water vapor through transpiration. [4, 5, 9, 12, 19]
Question 4: A news report states, 'The average annual precipitation in the Amazon rainforest has been consistently decreasing over the past 30 years.' This statement is a description of the region's:
- Tectonic activity
- Daily forecast
- Weather
- Climate (Correct answer)
Correct answer: Climate
Climate refers to the long-term average of weather patterns in a specific area, typically over 30 years or more. A statement about a consistent trend over three decades describes climate, not short-term weather conditions. [11, 13, 16, 17]
Question 5: The ozone layer is a critical component of Earth's atmosphere that absorbs the majority of the Sun's harmful ultraviolet (UV) radiation. In which atmospheric layer is the ozone layer primarily located?
- Troposphere
- Stratosphere (Correct answer)
- Mesosphere
- Thermosphere
Correct answer: Stratosphere
About 90% of the Earth's ozone is found in the stratosphere, which is the layer of the atmosphere located from approximately 10 to 50 kilometers above the surface. This concentration of ozone forms the protective ozone layer. [14, 18, 20, 21, 25]
Question 6: Many people believe Earth is warmer during the summer because it is closer to the Sun. Which statement BEST refutes this misconception and correctly explains the primary cause of seasons?
- The seasons are caused by the changing speed of Earth's rotation on its axis.
- The Sun produces more energy during certain times of the year, causing summer.
- The seasons are caused by the 23.5-degree tilt of Earth's rotational axis. (Correct answer)
- The seasons are caused by the Moon's gravitational pull influencing Earth's temperatures.
Correct answer: The seasons are caused by the 23.5-degree tilt of Earth's rotational axis.
Earth's seasons are a result of its rotational axis being tilted at an angle of 23.5 degrees. This tilt causes different parts of the Earth to receive more direct sunlight for longer periods of the day at different times of the year. When the Northern Hemisphere is tilted toward the Sun, it experiences summer, while the Southern Hemisphere experiences winter. [2, 6, 7, 10]
WCAS - Washington Comprehensive Assessment of Science Earth's Systems and Processes Questions and Answers
A geologist studying the rock cycle finds a sample of shale, a sedimentary rock, that has been subjected to intense heat and pressure deep within the Earth's crust, transforming it into slate.
Which of the following geological processes is responsible for this change?