Genetics is a big part of biology. Genetics allow us to understand why some humans have some traits and others dont. Such as blue eyes or different color hair. Genetic traits come from past generations. You usally have simular properties as your parents or grandparents. If both of your parents have brown hair it means there is a very high probably that you will have brown hair. Another thing that genetics helps us with is crossbreading. When people crossbread anything from plants to animals they need to intake the possibilities of genetics.