need options so i cant answer
<span>Not every member of a particular species (one kind of organism) must be able to reproduce in order for the species to survive. If you take homo sapiens for example (Humans) there are many males and females around the world who are sterile and unable to reproduce, yet you still see the human species flourishing. </span>
Elements in the first row (hydrogen and helium) will have outer electrons in the first energy level. Their principal quantum number is 1. Elements in the second row (lithium through neon) will have valence electrons in the second energy level with a principal quantum number of 2.