What function do capillaries serve in the cardiovascular system?
a.
carry blood to the brain
b.
return blood to the lungs
c.
control body temperature
d.
replace old blood cells

Capillaries are the smallest in the body. They carry oxygen and collect Carbon Dioxide. They bring the Carbon Dioxided blood to the lungs. In the lungs the blood gets oxygenated and goes back to the body. Capillaries also take nutrients to the body.

The answer is B.
return blood to the lungs

HOPE THIS HELPS 

Hey there! 
The correct answer to the question is B) return blood to the lungs.

Capillaries are the smallest blood vessels in our body. Capillaries allow the exchange of water, oxygen, carbon dioxide, nutrients, minerals, and wastes in the body. 

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