The motor unit is composed of both the skeletal and muscular systems.
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.
Yes o donors can donate to anyone
There are obviously A LOT of them. Like how your brain is slowly deteriorating, which is scary and dangerous. I can't cover everything but I have a website link you could visit that talks about this subject
https://www.drugabuse.gov/publications/research-reports/heroin/what-are-long-term-effects-heroin-use