The cell is the fundamental unit of life and requires certain basic functions, including:
1. a boundary that distinguishes inside from outside the cell yet allows materials to enter or leave the cell.
2. an "engine" to capture energy from the environment and convert it to a form useful to the organism.
3. a genome that can be transmitted to the next generation and is stable, but able to change.
4. a way to change in response to environmental changes, over both a short (individual organism) and long (generational) time frame.

Explanation:

A boundary that distinguishes inside from outside the cell yet allows materials to enter or leave the cell.

The cell needs a barrier for protection, rigidity and also for easy transportation.

"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."

a = executive branch; b = judicial branch