Final answer:
After meiosis I in oogenesis, a larger secondary oocyte and a smaller polar body are formed. The secondary oocyte holds the haploid number of chromosomes and may become fertilized, whereas the polar body generally degenerates.
Step-by-step explanation:
Oogenesis is the process by which primary oocytes develop into mature egg cells, or ova. During oogenesis, a primary oocyte completes the first meiotic cell division (meiosis I) to form secondary oocytes and a polar body. Specifically, after meiosis I in oogenesis is completed, one larger secondary oocyte and a smaller polar body are formed. The secondary oocyte is arrest at metaphase II and will only proceed to meiosis II if fertilization occurs. The polar body typically degenerates. The secondary oocyte contains the haploid number of chromosomes and is the cell that, if fertilized by a sperm, will complete meiosis II and potentially develop into a zygote.
This unequal division ensures that the resulting egg cell has sufficient cytoplasm and organelles to support early zygote development, as it contains most of these materials. The observed asymmetry in this cell division is essential because the egg contributes all the cytoplasm to the future zygote upon fertilization.