stimuli

definition: 
A thing or event that evokes a specific functional reaction in an organ or tissue
sentence: 
They are conditioned to respond to an auditory stimulus by, for example, dropping a block when a sound is heard through earphones. They had slower reaction times for visual and auditory stimuli, as well as subtle chorea, dystonia, and nystagmus
difficulty: 
very easy
toefl frequency: 
2
toefl classification: