Compressed and hardened layers of the sediments are called sedimentary rocks. These are secondary rocks and may also contain fossils of plants, animals and other micro-organisms that once lived on them. Sedimentary rocks can change into metamorphic rocks under great heat and pressure.
Rocks break down into small fragments known as sediments. These sediments are transported and deposited by wind and water, etc. When these sediments are compressed and hardened, the sedimentary rocks are formed.

(i) Red sandstone.
(ii) Students should do this exercise yourself.
Hint: Example of Red sandstone: Silli (stone slab used in roofs of SPS rooms in the foot schools of Delhi).

(a) The Taj Mahal is made up of white marble.
(b) The Red Fort is made up of red sandstone.
(c) The Humayun tomb is made up of red sandstone.

Differences between crust and core are

Differences between rocks and minerals are

Formation of rocks is a slow process because of the following reasons
(i) Primary rock is formed from molten magma then it cools and solidified.
(ii) Climate breaks the parent rocks into many smaller pieces.
(iii) Topography helps in weathering of rocks.
(iv) Time is one of the major factor in the formation of rocks

The differences between igneous and metamorphic rocks are as follow

Minerals are naturally occurring substances which have certain physical properties and definite chemical composition. Minerals are very important to humankind. Some are used as fuels. e.g. coal, natural gas and petroleum. They are also used in industries (iron, aluminium, gold, uranium, etc), in medicine, in fertilisers, etc

When igneous and sedimentary rocks undergo great heat and pressure, they form another type of rocks. So, that newly formed rocks is known as metamorphic rocks.

Rocks are very useful to us. The hard rocks are used for making roads, houses and buildings.

The process of transformation of the rock from one to another type under certain conditions in a cyclic manner is known as the rock cycle.

An extrusive igneous rock is formed from molten magma coming from the interior of the Earth comes on its surface, rapidly cools down and becomes solid whereas an intrusive igneous rock is formed when the molten magma cools down deep inside the Earth's crust.

The three major types of rocks are igneous rocks, sedimentary rocks and metamorphic rocks

Any natural mass of mineral matter that makes up the Earth's crust is called a rock

Crust, mantle and core are the three types of layers of the Earth.