The answer is B. They bring oxygen from the air into the body.
The lungs don’t produce or release oxygen so it’s not A. or D. The lungs do not transform oxygen into carbon dioxide cause our bodies need oxygen not carbon dioxide so it’s not C. Hope this helps!
The thread of protien called A. Fibrinogen helps form clots.
I can tell you that it is NOT B.
I got it wrong.
These had no leaves or roots, instead they had green photosynthetic stems which served as both anchors in the ground and photosynthetic surface.
