Define reversible change​

Which is the best predictor of the radioactive nature of an isotope? o the proton-to-electron ratio the neutron-to-proton ratio o the neutron-to-electron ratio the electron-to-proton ratio

This is the number of complete movements of a wave per second.

Anika asks eva to roll a basketball and then a bowling ball to her. which requires more force to roll, and why?