What functions do pheromones perform?
Pheromones are very important chemical messages that animals use to communicate to each other. Generally, pheromones tell animals of the same species a) the state of reproductive readiness (Male elk for example can tell if a female is ready to mate by smelling her urine to see if there are certain pheromones present indicating that she is ready) or b) the emotional state of the animal (sometimes fish release fear pheromones into the water to warn other fish of a predator)
Pheromones are typically inhaled by animals, and the brain determines what the pheromone means. Even humans can interpret what a pheromone means, even though we are not really aware that we are smelling a pheromone.
What functions do you perform on a regular basis and what percentage of your time do you spend on them?
If bacteria do not have organelles such as the nucleus how is it they can still perform the functions of life?
Tissues are made up of "like" cells that perform a specific function. Organs are tissues that act together to perform a specific function or functions. Organ systems are a group of organs acting together to perform a function or set of functions. All perform a function or functions but the level of complexity and the number of functions increases as the complexity increases.