I would have to say skin or hair
Explanation:
A slow, continuous process is defined as gradualism that occurs at slow rate but at a steady pace.
For example, stripes of a tiger develop slowly and at a steady pace so that they can hide in tall grass represents gradualism.
Whereas punctuated equilibrium is a process in which there is sudden and frequent changes that results in the formation of new species.
For example, species living in a sea for thousand of years breed and die over there and suddenly when there is change in sea level than animals must adapt represents punctuated equilibrium.
Ecosystems can only have so many organisms living in it before the vegetation’s can’t break it all down.