Final answer:
After about two months, symmetrical cell division in developing cells ends and they begin the process of cellular differentiation, forming specialized cells with distinct functions.
Step-by-step explanation:
At around the 2-month mark in cell development, symmetrical cell division ends and cellular differentiation begins. During symmetrical division, cells divide to produce two genetically identical daughter cells. This is a process that includes interphase and then the stages of mitosis: prophase, metaphase, anaphase, and telophase. The final stage telophase is characterized by the formation of two new daughter nuclei followed by cytokinesis, which is the division of the cytoplasm, resulting in two separate and identical cells.
However, after approximately two months, the cells stop dividing symmetrically and start differentiating into specialized cells with distinct functions. This differentiation is a crucial part of development, allowing for the complex organization of different cell types that make up the tissues and organs of a multicellular organism.