Basement membranes are thin, dense sheets of specialized, self- assembled extracellular matrix that surround most animal tissues. The basement membrane is a fibrous matrix composed primarily of glycoproteins, type IV collagen, and laminin that are secreted by the epithelial cells.
It is what makes plant stems, leaves, and branches so strong.
A clade is a group of species that includes an ancestral species and all of its descendents
