Pheromones are:

A) chemical signals
B) a type of sexual neurotransmitter
C) scents that are produced by males only
D) received by females only

Pheromones are chemical signals that are used by animals to communicate with each other. They can be used for a variety of purposes including mating, territorial marking, and signaling danger. Pheromones are not specific to a certain gender and can be produced by both males and females, and they can be received by individuals of the same or opposite sex.