for your first question well i still don't know what's actually my purpose in life , but of course i know that all of us has our own purposes and all of us has our own role in this life . second , death is the destination of all of us it will always be a part of the cycle it is not actually the end because when we die there will always be a beginning of life and i think reincarnation is true . and the last if i will simply explain it scientifically it is just because -  we lived in this world/planet because it is the only planet in the solar system that can actually sustain life there's enough oxygen , water and moderate heat from the sun and philosophically we lived in this world not because we have our own mission but because we are given the chance to experience and feel the life , we are given the chance to be loved by our family especially our parent and given the chance to choose what we want to be while we are still alive .