Question

The Earth is made up of several __________.
A) Concentric layers
B) Compositional layers
C) Structural layers
D) None of these

Answer 1

Hint:
The Earth is a dynamic planet and is constantly changing. It is made up of four separate layers. The denser and heavier material sank into the center and the lighter ones rose towards the top as the Earth cooled.

Complete Answer:
The earth, just like an onion, is made up of several concentric layers with one inside another. The crust is known as the uppermost layer over the earth’s surface and is the thinnest of all the layers. It is about only 5 km on the ocean floors and 35 km on the continental masses. The continental mass is called sial (si-silica and al-alumina) as the main mineral constituents of the continental mass are silica and alumina. The oceanic crust is on the other hand called sima (si-silica and ma-magnesium) as it mainly consists of silica and magnesium. The mantle is the next layer just beneath the crust which extends up to a depth of 2900 km below the crust. The next layer is the core and it is the innermost layer with a radius of about 3500 km; It is also called nife (ni-nickel and fe-ferrous i.e. iron) and is mainly made up of nickel and iron. The central core always has very high pressure and temperature.
The crust of the earth is made up of various types of rocks. Rocks can be of different textures, colors, and sizes. Three major types of rocks are there which are igneous rocks, sedimentary rocks, and metamorphic rocks. Rocks formed when the molten magma cools and becomes solid are called igneous rocks. They are also called primary rocks. Intrusive rocks and extrusive rocks are the two types of igneous rocks. Sediments are transported and deposited by water, wind, etc. These loose sediments compress and harden to form layers of rocks. Rocks formed in this way are known as sedimentary rocks. Under great pressure and heat, Igneous and sedimentary rocks can change into metamorphic rocks. For example, clay changes into limestone and slate into marble.

Thus, option (A) is correct.

Note:
In order to reach the center of the earth, which is not possible, a hole will have to be dug deep, about 6000 km, into the ocean floor.