The external layer of the human skin is called the epidermis and it replaces itself approximately every 27 days through shedding, which is known as exfoliation. Only this outer or surface layer of skin is replaced during the exfoliation process.
Gregor Mendel, the Moravian Augustinian monk who founded the modern science of genetics. Mendelian inheritance is a type of biological inheritance that follows the laws originally proposed by Gregor Mendel in 1865 and 1866 and re-discovered in 1900. These laws were initially very controversial.
Mendel's meticulous study produced astonishing results: Not only did the monk discover the idea of dominant and recessive traits, he was able to apply a consistent mathematical formula that explained the frequency with which each trait appeared. 1  His discoveries would be summarized into some basic principles: 1  That each inherited trait is determined by units (what we'd later call a gene) passed on independently of other traits. 2  That each trait is made up of two units, one received from each parent.