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.
He helped contribute to the cell theory by publishing a book about leaves being composed by cells. Louis Pasteur. Louis Pasteur contributed to the cell theory by disproving spontaneous generation. He was the first scientist to prove that cells can only form from pre-existing cells. He did this by creating an experiment that showed cells would only grow in broth if air was exposed.