* Blastula Development: The blastula is an early stage of embryonic development. It's essentially a hollow ball of cells called blastomeres.

* Rapid Cell Division: The blastula stage is characterized by rapid cell division (mitosis). This is essential for the embryo to increase its cell number and create the basic structure for future development.

* Interphase Dominance: Interphase is the longest phase of the cell cycle and is when the cell grows, copies its DNA, and prepares for mitosis. Because the blastula is primarily focused on generating more cells, the cells spend a significant amount of time in interphase to ensure they are properly prepared for division.

* Mitosis is Brief: Mitosis, the actual process of cell division, is relatively quick compared to the time spent in interphase.

In summary: The blastula stage is a period of rapid cell growth and division, so the cells spend the majority of their time in interphase to prepare for the next round of mitosis.