Most of the cells of the human body contain two sets of 23 chromosomes. Where did these chromosomes come from?
a- both sets came from the mother
b- both sets came from the father
c- a random number of chromosomes came from each parent
e-one set came from each parent

"menstrual cycle is a complex cycle that consists of several processes. order of occurrence of steps in menstrual cycle are as follows:

1. high progesterone levels maintain the endometrium lining of the uterus.

2. endometrium lining breaks down and low levels of estrogen stimulate the pituitary to release fsh and lh.

3. fsh and lh stimulates the follicles to develop and the oocyte to produce estrogen.

4. rising estrogen levels suppress fsh production and development of other follicles.

5. a spike in lh causes follicle to rupture.

6. a breakdown of corpus luteum causes progesterone level to drop."

substitution is the answer in this case