Explanation:
-social cohesion
-satey of people/property
that's for the first question, there may be more but that's all I've learnt now.
The second one is complicated since there is the mens rea so there is the intent to kill. So while it stops the people who this the punishment is worse that the act, it stops them. However for people who think the punishment is fine or that they can get away with it they will still do the act.
So it's complicated
