Russian physiologist Ivan Pavlov: A. discovered his groundbreaking findings by accident. B. realized that the dogs had learned to associate two stimuli-the sound of footsteps and food. C. studied the salivary response of dogs to different types of foods. D. All of these choices are correct.

The correct answer is D. All of these choices are correct

Explanation:

Ivan Pavlov was a famous physiologist know by his research in classical conditioning. During his early work, he investigated the digestive glands and gastric fuctions in dogs, later in children, by studying the salivary response trying different types of foods in different conditions. Along this first research, Pavlov realized, almost by accident, that dogs started to salivate before having the food in their mouths, just with the food smell, seeing the person who usually gave them the food, or even hearing the footseeps. Pavlov concluded that that behavior must had been learned by the dogs causing a response (salivate) to a stimuli (smelling, seen the person or hearing the footsteeps). This discovery lead to more research and experiments which gave him acknowledgement in this field.