Answer from cs61c-el (David Tung 16479725) for Question 2
PC-relative addressing is when the address is the sum of the PC and a constant in the instruction.  The problem is, that the instruction's address can only differ from the current address by a value of 2^16 words.  In very large programs, this can be a problem.  In our example, if the distance between Here and There is greater than 2^16 words (probably instructions, since each instruction takes 32 bits), then the assembler will be unable to specify a large enough value to add to the PC to reach the address of There.