1.what happens when the blood reaches the lungs?
A. it become red
B. it mixes with carbon dioxide
C. it leaves urine and carbon dioxide
D. it gives off carbon dioxide Ang absorb oxygen
2. Which system distributes oxygen - rich blood to the difference cell body ?
A. circulatory
B. Digestive
C. excretory
D. respiratory
3. Which organ filters unwanted materials coming from the blood?
A. kidneys
B. lungs
C. muscles
D. ribs
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