Answer: A
Explanation: The blood–air barrier (alveolar–capillary barrier or membrane) exists in the gas exchanging region of the lungs. It exists to prevent air bubbles from forming in the blood, and from blood entering the alveoli. ... The barrier is permeable to molecular oxygen, carbon dioxide, carbon monoxide and many other gases.
Understanding the evolution of HIV in an individual will help scientist understand how the virus responds to different drug regimes and will lead to better treatments
Drama! drama plays allow children to be creative and understand how people are different. it allows them to pretend and act out someone elses life.
If by inside, you mean staying indoors, then this is false. The average hours of sleep that people should get is between 7-8 hours. That would be 7/24 * 100 = about 30%. People must at least stay inside to sleep.
I hope I was able to answer your question. Have a good day.
