It can also be called a column.
Our bodies produce an enzyme called lactase. This enzyme helps our bodies digest lactose (a sugar found in milk). As we age, the amount of lactase our bodies produce decreases. Some people don’t produce as much as others. If you are lactose intolerant, it means your body doesn’t produce a lot of lactase. One option is to drink milk with lactase added to it.
Example: Lactaid
You would find layers in a sedimentary rock, because it has different types of other rock combined in it.