I have done some research, and from my limited experience with the game, I have to say that your answers are very wrong. According to Gamefaqs, and my personal experience, in Metroid II the meter starts off with 39. Once you kill 38 and get near the queen, she creates eight more, pushing it back up to 9, and making the total 46. If you include the Queen (which you should) then the total Metroids you have to kill is 47. There are 48 in the game if you count the Hatchling, but you don’t have to kill him. Hence, the correct answer to the question is 47.
I apologize for the lateness of my response, but I am quite sure it is accurate. Therefore I now have three correct answers. Yay me.
K that was already answered but what I meant was “Where are all the artifacts located?”
And they are all on the sanctuary(the entrance to the Impact Crater).