Luster means to give shine to a surface. Luster is a general idea of a mineral but you may need to be more specific. By specific I mean what kind of luster does the mineral have? Metallic, Non-Metallic, Vitreous, Resinous, Pearly, Greasy, Silky, or Adamantine. These are more specific types of luster than just saying luster.
Nondisjunction is the failure of one or more pairs of homologous chromosomes or sister chromatic.
Answer:
If I am correct it is when the weaker individuals or mutated individuals are killed of by other predators or by nature. Because they cannot survive this is natural selection because they are killed of by nature. Then if they are weak their species will go extinct, thus they are naturally selected to die and only the strong species remain.