Question

The first rocks were formed by the:

• A. Solidification of magma
• B. Solidification of the Earth's crust after melting.
• C. Pressing down of sediments at the ocean floor
• D. Materials that came out from the core of the Earth.

Answer 1

The correct option is B

Solidification of the Earth's crust after melting.

Correct option explanation

(b) The lighter substances floated on the surface to form the outermost layer of the Earth called the crust. As the surface of the Earth cooled, the crust solidified. This included the first rocks.

Incorrect option explanation

(a) Magma is the molten rocks below the crust.

(c) Pressing down sediments on the ocean floor will lead to the formation of sedimentary rocks.

(d) Materials that came out from the core of the Earth are in the form of metals and other substances, so they have no role in the rock formation.

As the surface of the Earth cooled, the crust solidified. This formed the first rocks, therefore, option (b) is correct.