Final answer:
Approximately 48 hours after fertilization, a zygote with four blastomeres can be expected, following a series of cleavage mitotic divisions.
Step-by-step explanation:
The zygote undergoes a process of cleavage during which mitosis occurs to produce two, four, and subsequently more cells. By the second day after fertilization, the single-celled zygote usually divides to form two daughter cells through mitosis. This mitotic process continues every 12 to 24 hours. By the end of day 2, it is possible to have a zygote with four blastomeres.
Therefore, approximately 48 hours after fertilization, a zygote with four blastomeres can be expected. This detailed timeline is essential to understand early stages of embryonic development and is a key point concerning human gestation.