Answer: A)
Explanation:
Children are at a higher risk of suffering negative effects from environmental hazards than adults, because children do not have fully developed immune systems. In addition, children have a higher exposure to environmental hazards, because they spend more time outside, on average, than adults. Children also take in more air per unit mass than adults, which means that they also take in more pollutants relative to their size.
The pulmonary veins carry oxygen-rich blood between the lungs and the heart.
It is actually the only vein in the boy that carries oxygenated blood. A clue to answering questions about veins is that veins are blood vessels that carry blood towards the heart while arteries carry blood away from the heart.
Answer:
this doesnt make sense please look over your question and correct the wording