I think the answer is Specialized cells!
Stage 3 because the person fev1 level is go down not up
Answer:
Artery, blood vessel, human heart, circulatory system, human
Explanation:
I put them in order of smallest to largest, I wasn't 100% sure that's what you wanted, but I hope this helps!
Answer:
mouth and or nose
Explanation:
air enters the respiratory system through the nose and mouth and passes down the throat and through a voice box.
