When Charlie the cat was a kitten, he just happened to be near the kitchen when his owner used an electric can opener to open a can of tuna for Charlie to eat. Curious about this strange sound, Charlie went to the kitchen and found the tuna in his dish. Now, no matter how deep Charlie's coma-like sleep is when someone uses the electric can opener for any reason, Charlie scrambles to his feet and sprints to the kitchen. This is an example of

operant conditioning.

Explanation:

Operant conditioning is the term given to a learning method, where an individual is trained to exhibit specific behavior after an element is presented to him. When this individual exhibits the required behavior, he receives a reward, otherwise he receives a punishment.

In the example given in the question above, the cat Charlie underwent an operative conditioning process, as it was trained to be in the kitchen whenever it heard the noise of the electric can opener. When Charlie answered that noise, it got a food that it liked. For this reason, whenever it hears the noise, it goes to the kitchen waiting for the reward.

hygrometers and hair thermometers (often found as part of hygrometers/psychrometers) can be used to measure humidity. barometers are used to measure atmospheric pressure, while anemometers are used to measure wind speed. so the 2nd and 4th choices should be the correct answers.

good question. i'll be looking into that. (this is a joke sir)