First polar body is formed after -
Ans. is 'b' i.e., First meiosisOogenesiso Oogenesis refers to the process of formation of ova from the primitive germ cells. Unlike fetal testis (in which spermatogenesis beings at puberty ), the fetal ovary begins oogenesis by 10 weeks of gestation.o The sequence of events in oogenesis are :The primitive germ cells undergo mitotic divisions to form oogonia (diploid cells). Oogonium is unique in that it is the only female cell in which both 'X' chromosomes are active.The oogonia proliferate by mitosis to form primary oocytes (diploid cells).Primary oocytes formed from the oogonia enter a prolonged prophase (diplotene stage) of the first meiotic division and remain in this stage until ovulation occurs after puberty .Primary oocytes completes the first meiotic division at puberty just before ovulation to form secondary oocyte (haploid cell) and 1st polor body.Secondary oocyte immediately begins second meiotic division but this division stops at metaphase and is completed only if the mature ovum (ootid) is fertilized with sperm. At that time second polor body (polocyte) is extruded and the fertilized ovum proceeds to form a new individual. Fertilization normally occurs in the ampulla of fallopian tube.
Mitosis
First meiosis
Second meiosis
Fertilization
Sex Hormones