Chromatography how would rf value change if developing chamber was uncovered

Bonus question: according to wikipedia, in chinese philosophy yin and yang "describes how seemingly opposite or contrary forces may actually be complementary, interconnected, and interdependent." what are some examples from the story that amy tan may have intentionally incorporated elements of yin and yang philosophy into this story? select 2.

In a communication, the media needs to be shared between devices

Each of the letters on the map above marks a body of water in southeast asia. which two letters represent gulfs