They're the only vein that carries oygenated blood
Homeostasis is the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing. Metabolism is the sum of all the chemical reactions that take in and transform energy and materials from the environment.
<span>The function of a cell wall has the same
function of the cell membrane; it protects the cell. Cell wall is made up of cellulose
that is only present in plant cells. Cellulose is a sugar that has a sheet like
structural carbohydrate. It is rigid that is used for support and provides protection
to the plant cell from damage. They cannot be dissolved in water. An example is
if you eat food that contains mostly of leaves. You will observe that you will
eliminate the same material as when you it. That is because our human body does
not have the enzyme that dissolves the cellulose.</span>
