Neutrons are not made up of smaller particles. They are considered fundamental particles, meaning they are not composed of anything smaller.

Here's a breakdown:

* Atoms: The building blocks of matter, made up of protons, neutrons, and electrons.

* Protons: Positively charged particles found in the nucleus of an atom.

* Neutrons: Neutral particles found in the nucleus of an atom.

* Electrons: Negatively charged particles that orbit the nucleus of an atom.

While protons are made up of quarks (up and down quarks), neutrons are considered fundamental particles and are not made up of anything smaller.