What are alveoli?
A. Tubes that connect the heart to the lungs
B. Air sacs used during respiration
c. Carbon dioxide molecules
D. Part of a red blood cell

B

Explanation:

Inside of your lungs, there are little pathways through which air flows, called bronchioles. Those bronchioles feed into tiny air sacs called alveoli, which fill with air when you breathe in and empty when you breathe out. Hope this helps!

typically, most spiders possess eight eyes. however, others have as many as 12, and some don't have any. these eyes are for detecting light from dark, deciphering shapes and for gathering their prey.

the "dirty dozen" chemicals banned in an international treaty are formally known as persistent organic pollutants, or pops. the united nations environment program provided this background on what they are and what they can do to humans and wildlife.

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