Question

why should the center of mass be kept low when designing a robot for pulling tasks?
to reduce the robots weight
to improve the robots stability
to make the robot taller
to increase the robots speed

Explanation:

The center of mass affects an object's stability. A lower center of mass means the robot is less likely to tip over during pulling tasks. Weight is determined by mass and gravity, not center - of - mass height. Making the robot taller would raise the center of mass (opposite of the goal here). Speed is related to motors, gears, etc., not center - of - mass height.

Answer:

To improve the robot's stability