Both amphibians and mammals rely on a double circulatory system. However, one large difference is .a. Amphibians do not have lungs b. Amphibians mix deoxygenated and oxygenated blood in their heart c. Amphibians have 2 atria d. Amphibians rely on Brownian motion e. None of the above

Explanation:

1. Amphibian's heart is three-chambered from which two are atria and only one is ventricle.

2. And there is two circulatory pathways having different routes.  

3.There is  mixing of oxygenated and deoxygenated blood in case of amphibians.

4. And in case of mammals there is no mixing of blood,, both the oxygenated and deoxygenated blood is completely separate.

5. Mammal's heart contain four chambers from which two are  atria and two are ventricle, and they completely separate both the oxygenated and deoxygenated blood.

"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. live where it’s cold and icy