How do microorganisms 'sense' their surroundings, if at all?
I've seen some swim around bouncing off each other, do they just go forward until they hit something? How do they find food? If they do hit something how do they know what it is?
What about different microorganisms, do they use different methods of moving and sensing?
What about microorganisms that don't move using flagella, do they just sit around until they hit food?