In what ways can you see microscopic organisms responding to stimuli? besides moving

The process of noticing environmental stimuli or stimuli arise from the body is called Sensation; the habit to pay less attention to a non-changing origin of stimulation promote change in responding to sensory events rather than perceiving constant stimulation.  The smallest noticeable difference of the  two stimuli-as stimuli get larger, differences must also become larger to be detected by an observer. 

name and explain one of the event that occurs during meiosis that increases the variation in offspring even more than simple reproduction?