Answer:
The answer is classical conditioning.
Step-by-step explanation:
In classical conditioning, a conditioned stimuls is associated with an unrelated consequence. This produces what is known as conditioned response. In the example, the sight of trees is associated with lightning, which results in fear.
Russian scientist Ivan Pavlov demonstrated his classical conditoning theories when he rang a bell before feeding a dog. In time, the dog would start salivating at the sound of the bell.