When we breathe in, oxygen enters our lungs and enters small sacs in our lungs called the alveoli. In the alveoli, the oxygen diffuses INTO the bloodstream through small blood vessels, called capillaries, that surround these alveoli. The oxygen is now in our bloodstream instead of our lungs and is used in cell respiration etc.
Oppositely, carbon dioxide is diffused FROM the bloodstream TO the alveoli, also through these capillaries. The carbon dioxide is now in the lungs instead of the bloodstream and when you breathe out, the carbon dioxide is breathed out out of your lungs.
Hope this helped, even if it helped a tiny bit. :)
The thickness of the uterine lining , becomes very thick...because when the level of hormone progesterone reaches its highest levels. according to Dr.X on yahoo answers.
<span>
</span>
That's D. Viral Reproduction.
It's not A cuz those are not bacteria
It's not B cuz diffusion deals with passive transport across membranes
It's not C cuz gamete formation deals with sex
The follicle is an integral part of the reproductive system of a woman. The follicle is composed of a cluster<span> of cells surrounding a single egg in the human female reproductive system which contains cilia to sweep the ovum to the uterus. Answer is follicle.</span>
