After the Earth developed a magnetic field and before single-celled photosynthetic organisms appeared on Earth, what was the atmosphere like? * 1 point
mostly hydrogen and helium
85% water vapor, 10% carbon dioxide, 5% nitrogen
78% nitrogen, 21% oxygen, 0.9% argon, 0.1% all other gases
there was no atmosphere before single-celled orgamisms

hi~~

i would say that hybridization occurs frequently in nature, because there are many types of hybrids that have occurred naturally, such as the mule (male donkey + female horse)

the answer to you question is   jet streams

"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."