Answer:
I would say a dense cloud of interstellar gas and dust.
Electron configuration<span> is the standard notation used to describe electronic structure of an atom. </span>
The Earth is divided into three chemical layers: the Core [Inner Core (D) and Outer Core (C)], the Mantle (B) and the Crust (A). The Core is predominantly composed of iron and nickel. Even after 4.5 billion years of cooling, the Earth's core remains very hot.
The answer is A. Every action has an equal and opposite reaction
