The border between the
transparent edge of the cornea and the white of the fibrous sclera is the limbus.
The limbus contains clusters of limbal stem cells that help to maintain the corneal
epithelium and to regulate corneal transparency and vision throughout life. The
limbus also acts as a boundary that protects the conjunctiva and its blood
vessels.
Decaying uranium atoms in the earth's crust result in Radon gas. Radon gas cannot be synthetically or commercially produced. It is produced as the result of the natural breakdown of uranium i.e. decaying uranium atoms. Radon gas is a naturally occurring radioactive gas. People are exposed to Radon gas via the inhalation and ingestion of the gas. Because it is found in the ground, water or building materials, Radon gas can enter work buildings as well as private dwellings.
Neurons function to process and transmit information. In vertebrate animals, neurons are the core components of the brain, spinal cord, and peripheral nerves.
It enters through the stoma.