Do Androids Dream? A Scene I found Interesting.

The scene I found most interesting so far in the book Do Androids Dream of Electric Sheep? was when Rick Deckard was administering a test on Rachel Rosen to see whether or not she was an android or not. When administering the tests he asks a lot of odd questions such as "Do you know how bullfights ended?"(Dick,49) or "In a magazine you come across a full-page color picture of a nude girl"(Dick,47). Why would any of these questions or statements have to deal with whether or not Rachel was a human or not?