NSCAS Science Standards 3 — Questions and Answers
Question 1: Which process in the water cycle returns water vapor to liquid water in clouds?
- Evaporation
- Precipitation
- Condensation (Correct answer)
- Transpiration
Correct answer: Condensation
Condensation is the process by which water vapor cools and changes back into liquid water droplets, forming clouds.
Question 2: A scientist wants to test whether fertilizer affects plant growth. Which variable should be kept the same in all groups?
- Amount of fertilizer
- Type of plant used
- Amount of sunlight given
- Both B and C (Correct answer)
Correct answer: Both B and C
A controlled experiment requires that all variables except the one being tested (fertilizer) remain constant, including plant type and sunlight.
Question 3: Which of the following structures is responsible for controlling what enters and leaves a cell?
- Cell wall
- Nucleus
- Cell membrane (Correct answer)
- Mitochondria
Correct answer: Cell membrane
The cell membrane is a selectively permeable barrier that regulates what substances enter and exit the cell.
Question 4: Fossils of marine organisms are found in rock layers high in a mountain range. What does this most likely indicate?
- The organisms once lived in mountains
- Tectonic forces uplifted the seafloor over time (Correct answer)
- The fossils were carried there by predators
- The ocean is gradually rising
Correct answer: Tectonic forces uplifted the seafloor over time
The presence of marine fossils in mountains indicates that tectonic activity uplifted rock layers that once lay on the ocean floor.
Question 5: Which type of wave requires a medium to travel through?
- Light waves
- Radio waves
- Mechanical waves (Correct answer)
- X-rays
Correct answer: Mechanical waves
Mechanical waves, such as sound, require a physical medium (solid, liquid, or gas) to propagate.
Question 6: What is the main role of decomposers in an ecosystem?
- Converting sunlight into food
- Breaking down dead organisms and recycling nutrients (Correct answer)
- Hunting and consuming prey
- Producing oxygen through photosynthesis
Correct answer: Breaking down dead organisms and recycling nutrients
Decomposers like fungi and bacteria break down dead organic matter and return nutrients to the soil.
Question 7: A student mixes two substances and observes bubbles forming and temperature rising. What type of change has most likely occurred?
- Physical change
- Chemical change (Correct answer)
- Nuclear change
- Phase change
Correct answer: Chemical change
Gas production (bubbles) and a temperature change are evidence of a chemical reaction, indicating a chemical change.
NSCAS Science Standards 3
Which process in the water cycle returns water vapor to liquid water in clouds?