When blood is in the lungs,
where oxygen is plentiful, oxygen easily binds to the first subunit and then quickly fills up the remaining ones. Then, as blood circulates through the body, the oxygen level drops while that of carbon dioxide increases. In this environment, hemoglobin releases its bound oxygen.
Answer:
D the train
Explanation:
The train is safe very fast and was the first built
<span>I believe it is C.
Waste is removed through a designated opening.</span>
In general for everyone, these are the most likely group of people i've chosen mature; grandparents(grandma,granddad), parents (mom,dad), your teacher.