What term refers to the reaction of animals to certain stimuli in their environment?

The term that specifically refers to the reaction of animals to certain stimuli in their environment is behavioral response. This concept encapsulates the various ways animals respond to different stimuli, which can include changes in the environment, presence of other animals, or other external factors. Behavioral responses can manifest in numerous ways, such as fleeing, approaching, vocalizing, or displaying aggression, and they play a crucial role in an animal's survival and adaptation.

Ethology is the study of animal behavior, particularly in natural environments, but it does not directly refer to the reactions themselves. Instinct refers to innate behaviors that organisms are born with, which are automatic responses to certain stimuli, while conditioning involves learning to associate a specific stimulus with a response through experience. Although all these terms relate to animal behavior, behavioral response is the most accurate descriptor for the reactions to stimuli in the environment.