I think its because when your upside down, your not breathing right. So its a way of trying to breathe correctly.
It might be 23% because 77% of water covers earth and most of the water is either polluted or salt water.
Answer:
adrenal gland smooth muscle in the walls of the aorta cardiac muscle in the right atrium

A prophage is a bacteriophage (often shortened to "phage") genome inserted and integrated into the circular bacterial DNA chromosome or exists as an extrachromosomal plasmid. This is a latent form of a phage, in which the viral genes are present in the bacterium without causing disruption of the bacterial cell.
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I think should do the trick A and D