Read the sentences below. They are the first part of a summary of the article. Atoms are the building blocks of everything. They are too tiny to be seen. Atoms are made up of electrons, protons and neutrons. Which answer BEST completes the summary? A Each atom has a special number and element B Each atom has some oxygen and hydrogen. с Each atom has an atomic number of 1. D Each atom is made up of 100 elements.​