It is quite normal that someone gets charged with multiple charges for the same act, for example to get charged with first degree murder, second degree murder, manslaughter, negligent killing, dangerous driving (if you run over someone with your car and kill them).
The prosecutor would have to prove that you killed someone except for the last charge. So someone is dead and you were the cause. Once that is proved, it may be the case that you fulfil all the criteria to be guilty of first degree murder, or maybe not. And if not, then it may be the case that you fulfil all the criteria to be guilty of second degree murder, or maybe not. And so on.
I think in the USA you may be convicted for multiple charges, but will only only be punished for the highest charge. So you won't get 40 years for 1st degree + 20 years for second degree + 10 years for manslaughter, but "only" the 40 years. In the future, you might manage to get the case re-examined and be found not guilty of 1st degree murder, with the 2nd degree charge standing.
Another situation is where you did two actions that were separate crimes, like kidnap and murder.
And very rarely a prosecutor will try to cajole a jury into giving a higher conviction by not charging the lower one. Assume there is a case where it is beyond any doubt whatsoever that someone committed at least second degree murder, but there is reasonable doubt about first degree murder. And the prosecutor charges only 1st degree but not 2nd degree murder. So the jury has only two possibilities: Not guilty (let someone walk who is definitely guilty of murder) or 1st degree murder (when there is reasonable doubt). That's a very dangerous game for the prosecutor.