AzM2 Science Assessment 2 — Questions and Answers

Question 1: Which type of rock is formed when molten magma cools and solidifies?

Sedimentary rock
Metamorphic rock
Igneous rock (Correct answer)
Composite rock

Correct answer: Igneous rock

Igneous rock forms when magma (underground) or lava (surface) cools and solidifies. Examples include granite and basalt.

The three rock types: Igneous (C) forms from cooled magma/lava (e.g., granite, obsidian, basalt). Sedimentary (A) forms from compressed layers of sediment (e.g., sandstone, limestone). Metamorphic (B) forms when existing rocks are transformed by heat and pressure (e.g., marble, slate). 'Composite rock' (D) is not a standard geological category. Answer C is correct.

Question 2: What is the function of the mitochondria in a cell?

To control cell activities and store DNA
To produce proteins for the cell
To provide energy by converting food into ATP (Correct answer)
To protect the cell from its environment

Correct answer: To provide energy by converting food into ATP

Mitochondria are the 'powerhouses of the cell' — they produce ATP (adenosine triphosphate) through cellular respiration, providing energy for cell functions.

Cell organelles: Mitochondria (C) conduct cellular respiration to produce ATP energy. The nucleus (A) controls cell activities and stores DNA. Ribosomes (B) produce proteins. The cell membrane (D) protects and regulates what enters/exits the cell. The famous mnemonic 'mitochondria is the powerhouse of the cell' helps students remember its energy-producing function. Answer C is correct.

Question 3: An object has a mass of 50 kg and accelerates at 2 m/s². According to Newton's Second Law (F = ma), what is the force applied?

25 N
52 N
100 N (Correct answer)
0.04 N

Correct answer: 100 N

F = ma = 50 kg × 2 m/s² = 100 N.

Newton's Second Law: F = ma. F = 50 kg × 2 m/s² = 100 N (Newtons). Answer C is correct. Answer A (25 N) = 50/2 (divided instead of multiplied). Answer B (52 N) adds instead of multiplies. Answer D (0.04 N) = 2/50. The unit Newton (N) = kg·m/s². Force, mass, and acceleration are three key quantities in classical mechanics.

Question 4: Fossils are most commonly found in which type of rock?

Igneous rock
Metamorphic rock
Sedimentary rock (Correct answer)
Volcanic rock

Correct answer: Sedimentary rock

Fossils form in sedimentary rock because organisms become buried under layers of sediment that slowly compress and harden over time.

Fossils are found primarily in sedimentary rocks (C) because: sediment (sand, mud) can bury organisms quickly, and layers build up and compress over time, preserving impressions or remains. Igneous rock (A) forms from molten material — extreme heat destroys organisms. Metamorphic rock (B) forms under intense heat and pressure — also destroys organic material. Volcanic rock (D) is a type of igneous rock. Answer C is correct.

Question 5: Which of the following describes a food CHAIN (not a food web)?

A diagram showing all feeding relationships in an ecosystem
A single pathway of energy transfer from one organism to the next (Correct answer)
A cycle showing how nutrients are recycled in nature
A map of an organism's habitat and resources

Correct answer: A single pathway of energy transfer from one organism to the next

A food chain shows a single, linear sequence of energy transfer (e.g., grass → grasshopper → frog → hawk). A food web shows all interconnected chains.

A food chain (B) is a single linear sequence showing energy flow: producer → primary consumer → secondary consumer → etc. (e.g., grass → rabbit → fox). A food web (A) is a complex diagram of all feeding relationships in an ecosystem. Answer C describes nutrient cycling. Answer D describes habitat mapping. The key distinction: chain = single path, web = network of paths. Answer B is correct.

Question 6: Earth revolves around the Sun in approximately 365.25 days. What astronomical concept does this represent?

Earth's rotation
Earth's revolution (one year) (Correct answer)
The lunar cycle
The tilt of Earth's axis

Correct answer: Earth's revolution (one year)

Earth's revolution is its orbit around the Sun, taking approximately 365.25 days — this defines one year. Earth's rotation is its spin on its axis (one day).

Key Earth motions: Rotation (A) = Earth spinning on its axis (takes ~24 hours = 1 day). Revolution (B) = Earth orbiting around the Sun (takes ~365.25 days = 1 year). The extra 0.25 days is why we have leap years every 4 years. The lunar cycle (C) is the Moon orbiting Earth (~29.5 days). Earth's axial tilt (D) causes seasons. Answer B is correct.

AzM2 Science Assessment 2

Which type of rock is formed when molten magma cools and solidifies?