Economic                 Geographic               Social
                   Aspect                      Aspect                      Aspect

A)                     1                                2                              3

1. the farms were rectangular in shape and perpendicular to the river;
     Not Correct ! (shape of farms is not economic)

2. the people put their efforts into developing agriculture;
    Not Correct !    (developing agriculture is not geographic)

3. the corvées (free labour) promoted the exchange of services.
   Correct !    (exchange of services is social)