3. Menstrual flow usually lasts for days. a 2-4 C. 3-8 b.3-5 d. 8-10 4. The union of male and female germ cells to form a zygote is called a. fertilization C. menstruation b. malnutrion d. ovulation 5. Egg cell is produced in the a. ovary C. Scrotum b. oviduct d. uterus