straight line motion

Hi, i wanna make a robot that has one axis and one motor driving two wheels , can it then move in straight line motion ? but im scared if the load for example on the right side were more , would it affect the straight motion ?

It's going to drift a little depending on difference in traction on each wheel.

Yes, you need some kind of feedback in order to keep it straight - at least over anything more than VERY short distances.