Answer:
1. Passive smoking is the inhalation of smoke, called secondhand smoke (SHS), or environmental tobacco smoke (ETS), by persons other than the intended "active" smoker. It occurs when tobacco smoke enters an environment, causing its inhalation by people within that environment.
2.The excretory system is the system of an organism's body that performs the function of excretion, the bodily process of discharging wastes. The Excretory system is responsible for the elimination of wastes produced by homeostasis
3.Excretion is the removal of waste products and this system must function properly in order to maintain homeostasis. The kidneys filter urea from the blood, which forms after proteins are metabolized and combine it with water to become urine, which is propelled by the ureters to the bladder.