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.
Answer: It is a synarthrosis joint because it cannot move.
Explanation:
After you realize that you are under stress, the next step is to identify the stressor you are facing. You can do this so you'll be able to recognize how you feel, and maybe even find the cause so you can avoid situations that make you stressed and learn to calm down.
It is A. sleeping deeply.
Delta waves, like other brain waves, are recorded with an electroencephalogram (EEG) and are usually associated with the deep stage 3 of NREM sleep, also known as slow-wave sleep (SWS), and aid in characterizing the depth of sleep.