Sue noticed that whenever she opened the door to the pantry, her dog would come into the kitchen and act hungry, by drooling and whining. She thought that because the dog food was stored in the pantry, the sound of the door had become a(n) .

Conditioned stimulus

Explanation:

Conditioned stimulus is the earlier neutral stimuli that gets linked with unconditioned stimulus and generate trigger to form conditioned response in the surroundings.

According to the question, as the door is shut is was previously neutral but after linking with opening door action which makes sound it acts as conditioned stimuli that is generating a hungriness indication to dog.Thus, dogs comes in pantry and displays his hunger through whining and other actions.

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answer; analytical;