ICAS Earth and Environmental Science 3 — Questions and Answers
Question 1: What is the term for the boundary where two tectonic plates move apart from each other?
- Convergent boundary
- Transform boundary
- Divergent boundary (Correct answer)
- Subduction zone
Correct answer: Divergent boundary
At divergent boundaries, tectonic plates move apart, allowing magma to rise and form new crust, as seen at mid-ocean ridges.
Question 2: Which part of the water cycle involves water vapor cooling and turning into liquid water droplets to form clouds?
- Evaporation
- Transpiration
- Condensation (Correct answer)
- Precipitation
Correct answer: Condensation
Condensation occurs when water vapor cools and converts to liquid, forming the tiny droplets that make up clouds.
Question 3: A soil sample has a pH of 4. What does this tell you about the soil?
- It is strongly alkaline
- It is neutral
- It is strongly acidic (Correct answer)
- It has high nutrient content
Correct answer: It is strongly acidic
A pH of 4 is well below 7 (neutral), indicating strongly acidic soil, which can affect plant nutrient uptake.
Question 4: What is the primary cause of seasonal changes in temperature experienced in the United States?
- Earth's changing distance from the Sun
- The tilt of Earth's axis relative to its orbit (Correct answer)
- Changes in the Sun's energy output
- Cloud cover patterns throughout the year
Correct answer: The tilt of Earth's axis relative to its orbit
Earth's axial tilt of about 23.5° causes different hemispheres to receive more direct sunlight at different times of year, creating seasons.
Question 5: Which of the following is an example of biomagnification?
- Plants absorbing sunlight more efficiently in summer
- Pesticides accumulating in higher concentrations in predators than in prey (Correct answer)
- Bacteria breaking down organic material in soil
- Water filtering through rock layers to become groundwater
Correct answer: Pesticides accumulating in higher concentrations in predators than in prey
Biomagnification occurs when toxic substances like pesticides accumulate at increasing concentrations at higher levels of a food chain.
Question 6: What kind of fault occurs when rocks on one side are pushed up and over rocks on the other side due to compressional forces?
- Normal fault
- Strike-slip fault
- Reverse (thrust) fault (Correct answer)
- Lateral fault
Correct answer: Reverse (thrust) fault
Reverse or thrust faults form under compression, causing one block to ride up over another and commonly creating mountain ranges.
Question 7: Which ocean zone receives enough sunlight for photosynthesis to occur?
- Abyssal zone
- Hadal zone
- Photic zone (Correct answer)
- Bathypelagic zone
Correct answer: Photic zone
The photic zone is the upper layer of the ocean (roughly top 200 m) where sufficient sunlight penetrates to support photosynthesis.
ICAS Earth and Environmental Science 3
What is the term for the boundary where two tectonic plates move apart from each other?