The iucn's red list is . a list of ecologically harmful invasive speciesb. a list of unidentified speciesc. a scorecard of international failures at conservationd. an updated list of species facing unusually high risk of extinctionan identification list of known species

An updated list of species facing unusually high risk of extinction.

Explanation:

The IUCN red list of threatened species also called as red data list. It is defined as the most comprehensive global conversation status of both animals and plants species.

The IUCN is a criteria to identify the extinction risk of lots of biological subspecies, and species. These criteria are relevant to all regions of the word, and all the biological species.

"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."