What type of intercellular chemical signal is released into the environment to modify the physiology and behavior of other individuals?

The correct answer pertains to a category of chemical signals known as pheromones. Pheromones are specific types of chemical signals released by an individual into the environment, which then influence the physiology and behavior of other individuals of the same species. This mode of communication is often observed in various animals, including insects, where pheromones can signal reproductive readiness, territory, alarm, or food sources.

In the context of intercellular chemical signaling, pheromones stand out because they are designed to travel across distances to elicit a response from another organism, thereby impacting social behaviors and interactions within a population. This characteristic is essential in species where chemical signaling plays a crucial role in survival and reproduction.

Other types of chemical signals, such as autocrine signals, act on the same cell that secretes them, and paracrine signals affect nearby cells, while neurotransmitters are involved in communication across synapses in the nervous system. Unlike pheromones, these other signaling methods do not typically involve the modification of behavior across different individuals or species in the same manner that pheromones do.