Final answer:
The location of the determination front in the presomitic mesoderm is set by genetic factors. Specific genes, including the Hox genes, play a vital role in the differentiation process and organogenesis during embryonic development.
Step-by-step explanation:
The location of the determination front or zone in presomitic mesoderm is primarily set by genetic factors. Embryonic development is a highly regulated process where organs develop from germ layers through differentiation. In this process, embryonic stem cells express specific genes that determine their eventual cell type, a sequence of events under tight genetic control. The Hox genes, for example, play a critical role by expressing transcription factors that regulate the development of specialized cells and tissues. This illustrates a conserved strategy that underpins the shared ancestry of diverse organisms and is key to the formation of the body axes and neural system from embryonic ectoderm during organogenesis.
Overall, differentiation in the presomitic mesoderm and the setting of the determination front are influenced by the intricate interplay between genetic instructions within the cells and the chemical signals in their environment, which together guide the growth and formation of the organism during embryogenesis.