Understand the definition of pheromones: Pheromones are chemicals released by an organism into the environment, affecting the behavior or physiology of others of its species.
Identify the category that best describes pheromones: Since pheromones are chemicals that communicate information between individuals, they fall under the category of chemical signals.
Review the options provided: hormones, visual signals, instinctive behavior, homeostasis, and chemical signals.
Eliminate options that do not fit: Hormones are internal chemical messengers, visual signals involve sight, instinctive behavior is a type of action, and homeostasis is the maintenance of internal balance.
Conclude that the correct category for pheromones is chemical signals, as they are external chemical messengers used for communication.