Have you had the chance to watch a tree grow over a span of several years? Did you notice that the tree grew thicker and taller?
Deep in the roots of the tree and high in the growing shoots are meristem cells. Each year, the meristem cells help the tree continue to grow. When the seed of a tree first starts to grow, what would happen if the cells did not differentiate?
N is your Nitrogen and H is your Hydrogen. Elements are just one specific kind of atom. You have two elements with names Nitrogen and Hydrogen. Therefore, you have two elements.
