RAM/FLASH adress lines

On LPC-4350-DB external RAM and FLASH use adress and data lines.
Why are the adress lines not connected (the resistors are not assembled)?

There are wires under these resistors, they are short-circuit. If user changes SDRAM or FLASH chips, it may be required to add series resistors to the data/address lines. So user will cut off the wires under resistors and then solder resistors of required nominal.