What connects the respiratory an circulatory systems? (apex learning vs)
a.) alevoli
b.) aorta
c.) hormones
d.) arteries

The correct answer is A) Alveoli                                                            

Explanation:

The respiratory system works directly with the circulatory system to give oxygen to the body. Oxygen is taken in from the respiratory system and delivered into blood vessels that then circulate oxygen-rich blood to tissues and cells.

Alveoli which are tiny, balloon-shaped air sacs sit at the very end of the respiratory tree and are arranged in clusters throughout the lungs. They are a crucial part of the respiratory system whose function it is to exchange oxygen and carbon dioxide molecules to and from the bloodstream.

Cheers!

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.