NAEP Science 2 — Questions and Answers
Question 1: Which layer of Earth's atmosphere contains the ozone layer that protects life from harmful ultraviolet radiation?
- Troposphere
- Stratosphere (Correct answer)
- Mesosphere
- Thermosphere
Correct answer: Stratosphere
The stratosphere, located roughly 10–50 km above Earth's surface, contains the ozone layer that absorbs most incoming UV-B and UV-C radiation.
Question 2: A student notices that a copper wire gets warm when electric current flows through it. This thermal energy is produced because electrons collide with:
- Other electrons moving in the opposite direction
- Atoms in the metal lattice (Correct answer)
- Photons of visible light
- Protons escaping from the nucleus
Correct answer: Atoms in the metal lattice
As electrons drift through the wire, they collide with vibrating metal atoms, transferring kinetic energy that appears as heat—this is electrical resistance.
Question 3: Two populations of birds become separated by a mountain range for thousands of generations. Over time they develop different beak shapes and cannot interbreed. This is an example of:
- Artificial selection
- Allopatric speciation (Correct answer)
- Genetic drift without selection
- Convergent evolution
Correct answer: Allopatric speciation
Allopatric speciation occurs when a geographic barrier isolates two populations, allowing them to diverge genetically until they become separate species.
Question 4: When a warm air mass rides up and over a cold air mass, the boundary between them is called a:
- Cold front
- Occluded front
- Warm front (Correct answer)
- Stationary front
Correct answer: Warm front
A warm front forms where advancing warm air gradually rises over retreating cold air, typically producing wide areas of steady precipitation.
Question 5: A chemical reaction in which energy is released to the surroundings, causing the surroundings to feel warmer, is described as:
- Endothermic
- Exothermic (Correct answer)
- Endergonic
- Entopic
Correct answer: Exothermic
Exothermic reactions release heat energy to the surroundings, resulting in a temperature increase in the environment.
Question 6: Which type of rock is formed when magma cools slowly beneath Earth's surface, resulting in large mineral crystals?
- Sedimentary
- Metamorphic
- Extrusive igneous
- Intrusive igneous (Correct answer)
Correct answer: Intrusive igneous
Intrusive (plutonic) igneous rocks cool slowly underground, giving crystals time to grow large—granite is a common example.
Question 7: A cell placed in a solution with a lower solute concentration than the cell's interior will:
- Shrink as water leaves by osmosis
- Stay the same because concentration is equal
- Swell as water enters by osmosis (Correct answer)
- Burst immediately because of active transport
Correct answer: Swell as water enters by osmosis
Water moves by osmosis from areas of lower solute concentration (the solution) into the cell where solute concentration is higher, causing the cell to swell.
NAEP Science 2
Which layer of Earth's atmosphere contains the ozone layer that protects life from harmful ultraviolet radiation?