Respuesta :
I think protons? I remember I did this question and it was either Protons or nuerons. Sorry if I'm wrong.
Answer:
Electrons
Explanation:
The majority of an atoms' mass comes from the protons and neutrons that make up its nucleus. Electrons are the least massive of an atom's constituent particles, with a mass of 9.11 x 10-31 kg and a size too small to be measured by current techniques.