<span>Veins have valves to make sure that blood flows in only one direction.</span>
I believe what you're looking for is alveoli.
Answer: I don't think it would be possible. Well actually there might be medicine that does that, but it might not be permanent.
Explanation:
hope this
Because people don’t understand the meaning of “orientation” (which means what your romantic/sexual attraction is. ie: gay lesbian straight) and “identity” (which refers to the issues of gender identity such seen by Transgenders, and is also your own internal personal sense of being)
