In a multicellular organism, nerve cells are different from muscle cells because -each cell type has a unique set of transcription factors and repressors, so it expresses a specific set of genes.
-each type of cell within a multicellular organism contains a different set of genes.
-random events within each cell regulate the expression of genes and result in different genes being expressed in different cells.
-cells gain and lose different genes during embryonic development, so each cell in an adult only has some genes from the original set.

"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."

c should be the answer

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation: