How Does a Single Atom Influence the Whole Universe?

A single atom can change the whole universe because it's like a tiny seed that grows into something huge. Imagine you have one grain of sand, if it starts rolling down a hill, it could cause an avalanche! An atom might seem small, but when it does things in the universe, it creates big changes. Like how atoms are inside stars, they help make the sun shine and let the moon orbit Earth.