What phase follows the zygote in the developmental process?

The developmental process following the formation of a zygote is known as gastrulation. During this phase, the single-layered blastula reorganizes into a multi-layered structure called the gastrula. This is a crucial stage in embryonic development as it establishes the three primary germ layers: the ectoderm, mesoderm, and endoderm, which later give rise to all tissues and organs in the body.

In contrast, meiosis is a type of cell division that reduces the chromosome number by half and is typically involved in the production of gametes, not in the development of the zygote. Interphase is a stage in the cell cycle where the cell prepares for division and does not specifically refer to developmental processes following the zygote. Differentiation, while it does occur later in development when cells become specialized, comes after gastrulation has established the germ layers. Thus, gastrulation is the correct phase that directly follows the zygote in development.