Formaldehyde is an organic compound.
A single replacement reaction, sometimes called a single displacement reaction, is a reaction in which one element is substituted for another element in a compound. The starting materials are always pure elements, such as a pure zinc metal or hydrogen gas, plus an aqueous compound.
The Big Bang is a scientific theory about how the universe started, and then made the stars and galaxies we see today. ... Then about 13.8 billion years ago, space expanded very quickly (thus the name "Big Bang"). This started the formation of atoms, which eventually led to the formation of stars and galaxies.