QUESTION:
I would like to know why the scientists picked just one spot on Mars to
study with the Pathfinder instead of picking lots of spots to study? 

ANSWER from Cheick Diarra on November 27, 1996:
The scientists selected one site to investigate with the rover because the
rover can cover only a small area of Mars. In the future, next generation
of rovers would be able to move faster and live longer on Mars. This would
make it possible for a single mission to investigate more than one area. 

But the rover we are sending will be able to exmaine lots of different
rocks within its small area.  In the past landings on Mars (Viking), we 
just landed and stayed put.  We could only examine what we could reach out 
and touch. So having a rover that can move even a small difference away gives
us an exciting new capability.