cortices. 1  1a (1) : the outer or superficial part of an organ or bodily structure (such as the kidney, adrenal gland, or cerebellum or a bone); especially : cerebral cortex (2) : the proteinaceous usually pigmented layer of a hair below the cuticleb : the outer part of some organisms (such as paramecia)
If a toenail has completely fallen off, it can take up to 18 months for it to grow back. A toenail can take longer to grow back if the nail bed has permanent damage. In some cases, old nails do not completely fall off, and they act as a protective...
As mentioned before, lizards have the ability to regenerate their tails. It takes about nine weeks for a lizard to grow their tail back. Within the first three weeks, the lizard's tail is a dark stump of lymph vessels. When the tails grow back, they regenerate from the inside-out. After six weeks, the whole shape of the tail has been regenerated.