Whenever Martin visited his grandfather, he would have to walk past a house with a large dog in the yard. The dog would bark viciously at Martin, and this scared him. Years later, Martin became anxious whenever he visited his grandfather, even though the dog is no longer there. Which describes why Martin became anxious

I looked this question up, but was unable to find the answer choices online. So I will give you a general answer and a detailed explanation that will likely help you.

What describes why Martin became anxious is classical conditioning.

Explanation:

Classical conditioning basically refers to association. A person or an animal learns to associate a certain stimulus to a certain response. Every time that stimulus occurs, the response will also occur.

In Martin's case, the dog barking viciously at him scared him. Since that happened every time he went to visit his grandfather, he would become anxious whenever he had to go there. Martin associated a stimulus (going to his grandfather's house) to a response (feeling anxious). Now, years later, even though the dog is no longer there, the stimulus still produces the same response - visiting his grandfather still makes Martin anxious.