3. Core memory would not erase itself when its power 
   source was removed. Give reasons why this is a 
   valuable property.

There are many acceptable answers here. In mission 
critical situations such as spacecraft or even automobiles 
it would permit the system to restart quickly without loss
of data. Complex calculations could be continued from the point
where power had stopped. One could analyze the cause of any
problems that might be the result of a programming error. It
would permit operators to cut the power as a means of stopping
the computer in an emergency.