Question

1. Give a brief account on different types of rocks
2. How are rocks and minerals useful for human beings? Hors
3. It is impossible to reach the centre of the earth. Give reasons. on
4. How are sedimentary rocks formed from sediments ?
5. Granite and limestone are changed into gneiss and marble respectively. Give reasons.​

Answer 1

Answer:

There are three kinds of rock: igneous, sedimentary, and metamorphic.

Igneous rocks form when molten rock (magma or lava) cools and solidifies. Sedimentary rocks originate when particles settle out of water or air, or by precipitation of minerals from water. They accumulate in layers. Metamorphic rocks result when existing rocks are changed by heat, pressure, or reactive fluids, such as hot, mineral-laden water. Most rocks are made of minerals containing silicon and oxygen, the most abundant elements in the Earth’s crust.

In This Section

EXHIBIT

Igneous Rocks

Igneous rocks solidify from molten rock (called magma within the Earth and lava on the surface).

EXHIBIT

Sedimentary Rocks

Sedimentary rocks are layered.