What a question. I suddenly feel very humble because that is a question that I should have asked myself but I never have. Thank you. I asked my friends to help me and here are the responses.
I have, discovered that electrons are still fundamental particles BUT they have found two types of electrons a negatively charged electron and a positively charged electron so they are now called leptons. That does not however answer your question. What is a lepton made of?
My friends are quite correct Protons and Neutrons are no longer fundamental particles. (A fundamental particle is a particle that is not made of anything else) It was in 1911 that a scientist called Rutherford first discovered the proton and neutron. Then,in 1968, other scientists found that protons and neutrons were made up of fundamental particles called quarks. The next question of course is what are quarks made of?
To be continued