Epithelial tissue
Steerage is at the bottom of the ship always.
Gives them a feeling of power. I don't believe they "always" want to be on top - at least, not all girls. Different people have different tastes.
The idea or belief that north should always be up and east at the right was established by the Egyptian astronomer Ptolemy (90-168 AD). "Perhaps this was because the better-known places in his world...