PLEASE HELP 1. Although organisms often share similar genes, they may have significant phenotypic differences. Which statement explains why this may occur?

Although DNA is always expressed, the gene products may not always be used by the organism.
Gene expression is controlled by regulatory genes, regulatory elements, and transcription factors.
Not all organisms have control mechanisms, so genes may sometimes be overexpressed or not expressed at all.
The types of nitrogenous bases differ between organisms, causing gene sequences to produce different proteins.

"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."

the glands which are associated with each description is given below:

voluntary muscles are controlled by the cerebellum.