Answer:
the atom
Explanation:
The bread and cheese separately represent the atom because both bread and cheese are different from one another and we cannot assume it as a molecule because molecules formed when the group of atoms combine together by making bonds with each other and we know that bread and cheese did not make bonds with each other, they only attached, so we called them atoms not molecule.
The Mr is the mass numbers of each element added up so…. Fe = 56, O=16, H=1 … now add these up with the number of each element -> there’s 1 Fe, and 3 Os and 3 Hs as they are in brackets with a 3 outside-> (56+16+16+16+1+1+1=107) … your answer is 107