Why does the Earth rotate
A. Because the earth is formed from cold gas is collapsing due to gravity
B. Because the matter in the nebula that formed earth was spinning
C. Because earth form is more than 99% of the mass of the solar system
D. Because the hydrogen Adams inside the nebula fused to form helium

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers

it should be d) transitional fossils.

they show the gradualism of evolution throughout a period of time