What term describes changes in the environment that are detected by receptor cells?

The term that describes changes in the environment detected by receptor cells is "stimuli." Stimuli refer to any external or internal changes that can trigger a response in an organism. These changes can come from various sources such as light, sound, temperature, pressure, or chemical signals. When receptor cells detect these stimuli, they convert them into signals that the nervous system can interpret, leading to appropriate responses.

In this context, conditions refer to the state of the environment rather than specific changes. Responses describe the actions or reactions of the organism to the stimuli, and reactions are often used interchangeably with responses but do not specifically denote the initial changes that trigger these actions. This helps clarify the process of how organisms interact with their surroundings through the detection and response to stimuli.