In the nuclear decay given below :

_ZX^A ⟶ _Z+1Y^A ⟶ _Z-1B^A-4 ⟶ _Z-1B^A-4

The particles emitted in the sequence are :

1. α, β, γ
2. β, α, γ
3. γ, β, α
4. β, γ, α

(a) Name the process, nuclear fission or nuclear fusion, in which the energy released per unit mass is more?

(b) Name the process, fission or fusion which is possible at ordinary temperature.

What is the source of energy of sun or stars?