Final answer:
A pheromone is a chemical signal used for communication between members of the same species, causing behavioral or physiological changes. These are secreted and can influence various behaviors, such as mating, marking territory, or indicating danger. Hence, the correct answer is option (b).
Step-by-step explanation:
A pheromone is a type of chemical signal used in intraspecific communication. That means it's used for communication within the same species. These chemical messengers are released by one individual and received by another, causing some sort of behavioral or physiological response.
For example, pheromones can be used by animals to attract mates, define territory, warn others of danger, or establish social bonds among group members. In some species, like insects, they can also be used to mark trails to a food source. Human pheromones, such as axillary steroids, are less understood but are believed to affect our perceptions of other people, such as in the synchronization of menstrual cycles among women in close proximity.
Pheromones are not visual, auditory, or tactile; they are distinctly chemical.