Sam was working under a geologist. He lost his balance and dropped the bags containing igneous rocks and sedimentary rocks and the rocks got mixed. How would he separate them?

1. Igneous rocks are hard.
2. Igneous rocks are crystalline.
3. Sedimentary rocks have strata showing layers.
4. Sedimentary rocks are soft.

Assertion (A): Igneous rocks are called primary rocks.

Reason (R): They were the first to be formed.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R does not explain A.
3. A is true but R is false.
4. A is false but R is true.

The following pairs are the types of rocks on the basis of agents of their formation. Which of the following is incorrect?

1. Lacustrine : lake beds
2. Aeolian : sand particles
3. Glacial : ocean floor
4. Riverine : flowing waters of rivers.

The alteration of the composition or structure of a rock by heat, pressure or other natural agency:

1. Hypobyssal
2. Metamorphism
3. Compaction
4. Cementation