During a stage of development in humans called 1) ____________________, the
hormone producing pituitary gland in the brain starts to release the chemicals 2)
_____________________ and 3) _____________________ in the blood.
The egg cells in the ovary grow making the estrogen level to increase which
inhibits the levels of FSH and telling the pituitary gland to pump out more LH
(follicular phase). The LH causes the mature egg cell to come out from the ovary
going to the fallopian tube through ovulation (ovulatory phase).
Pregnancy occurs only if the 4) ____________________ is fertilized by the
sperm cell. In preparation for the implantation of a fertilized egg, the uterine wall
thickens with fluid and nutrients. (luteal phase)
If fertilization does not occur, the female hormones estrogen and
progesterone levels go down, the uterine lining starts to degenerate, forming the
menstrual flow (menstrual phase).
The description that you have just read is one of the changes in females
during adolescence period which is called 5) ____________________ .

follicle stimulating hormone (FSH) menstruation
egg cell luteinizing hormone (LH)
puberty