Step 1 : Introduction to the question "9. Atoms consists of which particles?"
...1. Protons-Neutrons-Hadrons 2. Protons-Neutrons-Electrons 3. Protrons-Neutrons-Positrons 4. Protons-Neutrons-Photons Atoms are the smallest units of matter that can take part in a chemical reaction, and which cannot be broken down chemically into anything simpler.