What occurs in the first step of oogenesis during meiosis?

• A. The primary oocyte begins meiosis I and arrests in prophase I.
• B. The secondary oocyte completes meiosis II to form a mature ovum.
• C. The primary oocyte undergoes mitosis to produce two identical cells.
• D. The oogonium divides by meiosis to form a primary oocyte.

Answer: (A)

Verified step by step guidance

1. Understand that oogenesis is the process of forming female gametes, or ova, through meiosis.
2. Recognize that the first step in oogenesis involves the transformation of oogonia into primary oocytes.
3. Learn that primary oocytes begin meiosis I but do not complete it immediately; they arrest in prophase I until puberty.
4. Note that during puberty, hormonal changes trigger the continuation of meiosis I, leading to the formation of secondary oocytes.
5. Remember that the secondary oocyte will only complete meiosis II if fertilization occurs, resulting in a mature ovum.