Is this correct or no? EXPLAIN!

In which of the following cases is work being done on an object? question 2 options: pushing against a locked door carrying a box down a corridor pulling a trailer up a hill suspending a heavy weight with a strong chain

Which changes of state do the labels represent? a: b: c:

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