The fortress problem involves a fortress and marching soldiers, ...

[Themember4]

The fortress problem involves a fortress and marching soldiers, while the radiation problem involves a tumor and rays. Therefore, the two problems have very different
 
  a. surface features.
  b. operators.
  c. structural features.
  d. mental sets.

Question 2

People are most successful at noticing an analogous relationship between problems if they focus on
 
  a. surface features.
  b. structural features.
  c. operators.
  d. mental sets.

[scrocafella]

Answer to Question 1

a

Answer to Question 2

b