Final answer:
A diploid oogonium undergoes meiosis to produce one large ovum and one or more polar bodies. The ovum becomes the mature female gamete, while polar bodies degrade.
Step-by-step explanation:
In animals, a diploid oogonium undergoes meiosis to produce one large ovum and one or more smaller polar bodies that later degrade. This process is part of oogenesis, which begins before birth with the diploid oogonium undergoing mitosis to form a primary oocyte. The primary oocyte undergoes meiosis I to form a secondary oocyte and a polar body. If the secondary oocyte is fertilized, it completes meiosis II, ultimately producing a haploid ovum and an additional polar body. The ovum contains most of the cytoplasm, nutrients, and organelles, becoming the mature female gamete. In contrast, polar bodies, which contain little more than DNA, eventually degrade as they do not contribute to fertilization.