The answer is A. Isotopes only differ in the number of neutrons in the nucleus of their atoms. Otherwise, all other subatomic particles are the same. The isotope with the more neutrons in its nucleus is therefore, heavier (have higher mass number). They share the same chemical properties but have slight physical differences such as boiling points with the heavier element having a slightly higher boiling point that the lighter element.
I believe the correct response would be A. The cumulative nature of science. How experimental evidence and ideas made by many scientists have accumulated and or built up to have a more understandable and or clear view of a particular scientific topic, and or principle.
I believe the third choice is correct.
This can be proven by the fact that to find the molar mass of a compound, you simply add the molar masses of all the atoms within the compound
Hope this helps
It should be the answer b but I’m not to sure