Isotopes are elements with same atomic number Z= number of protons but different mass number A, where A= Z+N, N= number of neutrons which is variable. As for radioisotopes, I’ve never heard of them before !
Answer: We can tell how life existed on earth and how different plants and animals are related to each other. Often we can work out how and how and where they lived, and use this information to find out about ancient environments. Fossils can tell us about the past.
Explanation
2. third quarter 7. first quarter 1. waxing gibbous 8. waning gibbous 5. waning cresent 3. waxing cresent
