After fertilization, the zygote will enter which process?

• A. Mitosis
• B. Meiosis
• C. Cytokinesis
• D. Apoptosis

Answer: (A)

After fertilization, development proceeds through rapid mitotic divisions of the zygote, a process known as cleavage. These mitotic divisions increase the number of cells without a large increase in overall embryo size, setting up the multicellular structure of early development. Meiosis would create gametes and happens before fertilization, so it’s not what follows fertilization. Cytokinesis occurs during each cell division to split the cytoplasm, but the overarching process describing the zygote’s sequence of divisions is mitosis. Apoptosis is programmed cell death and not the typical first step in post-fertilization development. So the zygote enters mitosis.