Rock Cycle Quiz diagram illustrating the transformation of rocks through various geological processes.

Let’s go through each question one by one, using what we know about the rock cycle.

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Question 1: Which of the following is not a type of rock?

The three main types of rocks are:
- Igneous (formed from cooled magma or lava)
- Sedimentary (formed from layers of sediment pressed together)
- Metamorphic (formed when existing rocks change due to heat and pressure)

“Limestone” is actually a *type* of sedimentary rock — so it IS a rock. But wait — let’s look again at the options:

A. Limestone → This is a sedimentary rock
B. Igneous → Type of rock
C. Metamorphic → Type of rock
D. Sedimentary → Type of rock

Wait — that can’t be right. All four seem like they could be rocks? But the question says “which is NOT a type of rock.”

Actually, here’s the trick: Igneous, Metamorphic, and Sedimentary are the *three major categories* of rocks. Limestone is a specific example of a sedimentary rock — but it’s still a rock.

But maybe the question is trying to say: which one is not one of the *main types*? In that case, limestone is not a main category — it’s a subtype.

Looking back at standard science curriculum: The three main rock types are igneous, sedimentary, metamorphic. Limestone is a kind of sedimentary rock — so if the question means “which is not one of the three main types,” then A. Limestone would be the answer.

Yes — that makes sense. So:

✔ Final Answer for Q1: A. Limestone

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Question 2: What process is necessary to change a sedimentary rock into a metamorphic rock?

Metamorphic rocks form when existing rocks (including sedimentary ones) are changed by heat and pressure deep underground. They don’t melt — if they melted, they’d become magma and then igneous rock.

So:

A. Weathering and erosion → breaks down rocks, doesn’t make metamorphic
B. Heat and pressure → YES! That’s how metamorphic rocks form
C. Melting → turns rock into magma → becomes igneous later
D. Solidification → that’s when magma cools → becomes igneous

✔ Final Answer for Q2: B. Heat and pressure

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Question 3: How do sediments become sedimentary rock?

Sediments are tiny pieces of rock, sand, mud, etc. To turn them into solid sedimentary rock, two things happen:

1. Compaction — layers pile up and squeeze the sediments together
2. Cementation — minerals glue the sediments together

This whole process is called lithification.

Now look at the choices:

A. Compaction and cementation → YES! Exactly right
B. Cooling and solidification → that’s for igneous rocks
C. Melting and erosion → melting makes magma; erosion breaks things down
D. Heat and/or pressure → that makes metamorphic rocks

✔ Final Answer for Q3: A. Compaction and cementation

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Final Answer:
1. A
2. B
3. A