What is the difference between an artery and a vein? 1 An artery carries blood away from the heart; a vein carries blood to the heart.
2 An artery is responsible for carrying blood; a vein is responsible for gas exchange.
3 An artery is responsible for gas exchange; a vein is responsible for carrying blood.
4 An artery carries blood to the heart; a vein carries blood away from the heart.

1 An artery carries blood away from the heart,a vein Carrie's blood to the heart

1. An artery carries blood away from the heart; a vein carries blood to the heart.

Explanation:

An artery carries away oxygen-rich blood from the heart to other body parts, whereas a vein takes blood low in oxygen back to the heart for oxidation.

the correct answer is:

a population changes in response to a change in the environment.

"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."