Fertilization is the name given to the fusion of male and female gametes. By themselves, female egg cells -- called ova -- and male sperm cells cannot grow and divide. However, once a sperm cell breaks through the egg cell membrane, the genetic material combines and the new organism begins to grow and develop as a living thing.
Lactose intolerance is when your body can't break down or digest lactose. Lactose is a sugar found in milk and milk products. Lactose intolerance happens when your small intestine does not make enough of a digestive enzyme called lactase. Lactase breaks down the lactose in food so your body can absorb it.
