Stanford Achievement Test Stanford Achievement Science Concepts 3 — Questions and Answers
Question 1: What is the basic unit of life?
- Atom
- Molecule
- Cell (Correct answer)
- Tissue
Correct answer: Cell
The cell is the smallest unit that can carry out all basic life functions, making it the fundamental unit of life.
Question 2: When water vapor cools and changes into liquid water, this process is called:
- Evaporation
- Condensation (Correct answer)
- Precipitation
- Sublimation
Correct answer: Condensation
Condensation occurs when water vapor loses heat energy and changes into liquid water, as seen on a cold glass.
Question 3: Which of the following is a renewable energy source?
- Coal
- Natural gas
- Solar energy (Correct answer)
- Petroleum
Correct answer: Solar energy
Solar energy is renewable because the sun continuously produces light and heat that can be converted to electricity.
Question 4: In a food chain, which organism is always the producer?
- Deer
- Grass (Correct answer)
- Fox
- Hawk
Correct answer: Grass
Producers are plants that make their own food through photosynthesis, forming the base of every food chain.
Question 5: What causes the seasons on Earth?
- Earth's distance from the Sun changing throughout the year
- Earth's tilt on its axis as it orbits the Sun (Correct answer)
- The Moon's gravitational pull on Earth
- Variations in the Sun's brightness
Correct answer: Earth's tilt on its axis as it orbits the Sun
Earth's 23.5-degree axial tilt causes different parts of the planet to receive more or less direct sunlight as it orbits the Sun.
Question 6: Which gas makes up the largest percentage of Earth's atmosphere?
- Oxygen
- Carbon dioxide
- Nitrogen (Correct answer)
- Argon
Correct answer: Nitrogen
Nitrogen makes up about 78% of Earth's atmosphere, while oxygen accounts for about 21%.
Question 7: What is the term for an animal that eats only plants?
- Carnivore
- Omnivore
- Herbivore (Correct answer)
- Predator
Correct answer: Herbivore
Herbivores are animals that consume only plant matter, such as cows, rabbits, and deer.
Stanford Achievement Test Stanford Achievement Science Concepts 3
What is the basic unit of life?