Brenda is getting the pressure in her eye measured at the op…
Brenda is getting the pressure in her eye measured at the ophthalmologist. To do so, they play a brief tone and blow a puff of air into her open eye which causes her to blink. Over repeated trials, Brenda blinks when she hears a similar tone, even in the absence of the puff of air. The tone has become a(n) _________.