Final answer:
The normal process of programmed cell death that results in the loss of early stage embryonic tissues such as webbing between digits is known as apoptosis. Apoptosis is essential for proper embryological development, including the formation of distinct fingers and toes, and in the maturation of the immune system.
Step-by-step explanation:
During normal embryonic development, early stage tissues such as gill pouches and tail, as well as tissue between digits, is lost at the appropriate time due to the normal process of programmed cell death, also known as apoptosis.
Apoptosis is a critical process in vertebrate embryological development, including the elimination of web-like tissue between a developing organism's fingers and toes. This is driven by cell signaling mechanisms which ensure that cells which are no longer needed or that might be harmful to the organism are systematically destroyed, allowing for the proper formation of distinct fingers and toes. As such, in the development of the xylem, apoptosis allows for the maturation of this tissue, contributing significantly to the development of functional organs and structures during embryogenesis.
Another instance of the importance of apoptosis in cellular regulation is seen in the development of the immune system, specifically T-cells, where it prevents the survival of cells that mistakenly target the body's own proteins, potentially leading to autoimmune diseases.