Which is not the following of the ways that bacteria can be helpful to human? A. They prevent harmful bacteria on your skin from getting into your body.

B. they break down food in your digestive system

c. they act as decomposers in ecosystem

d. they prevent the spread of the common cold

The answer is B

Explanation:

they don't prevent harmful bacteria (a)

decomposing thing doesn't help people directly(c)

and they don't prevent the spread of the common cold(d)

the diploid number of chromosomes is sometimes represented by the symbol 2n. for the fruit fly, the diploid number is 8, which can be written as 2n = 8, where n represents twice the number of chromosomes in a sperm or egg cell.

"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."