WAEC 2022 Geography · Question 45

Which of the following pairs are characteristics of igneous rocks? They I. are stratified II are metamorphosed…

Question

Which of the following pairs are characteristics of igneous rocks? They I. are stratified II are metamorphosed rocks III. are crystalline IV. originate from molten magma

A.I and II only
B.II and III only
C.II and IV only
D.IIl and IV only

Answer: D. IIl and IV only

Explanation written with AI and checked against the answer key

Step 1: Analyze the question We need the statements that correctly describe igneous rocks.

Step 2: The concept Igneous rocks (e.g., granite, basalt, gabbro) form when molten magma or lava cools and solidifies. Because of this origin, they have particular features:

They are crystalline, made of interlocking mineral crystals. Slow cooling underground gives large crystals (granite), and fast cooling on the surface gives small crystals (basalt).
They originate from molten magma (or lava).
They are not stratified (not layered into beds). Layering is typical of sedimentary rocks.
They are not metamorphosed. Metamorphic rocks are changed by heat and pressure, such as marble from limestone.

Step 3: Check each statement

I. Are stratified: False. This describes sedimentary rocks.
II. Are metamorphosed rocks: False. This describes metamorphic rocks.
III. Are crystalline: True.
IV. Originate from molten magma: True.

Step 4: Answer Statements III and IV are correct, so the answer is D (III and IV only). The "IIl" in option D is just a typing quirk for "III".

Tip: Link each rock type to a key word:

Igneous → fire/magma, crystals
Sedimentary → strata/layers, fossils
Metamorphic → changed by heat and pressure

If you see "stratified" or "fossils", think sedimentary, and eliminate those options quickly.

AI can make mistakes. Report anything that looks wrong.