The kidneys and bladder are primarily involved in which body system?

The kidneys and bladder are primarily involved in the excretory system, which is responsible for the removal of waste products from the body and the regulation of fluid balance. The kidneys filter the blood to produce urine, which contains waste materials such as urea, creatinine, and excess salts. This urine is then transported to the bladder, where it is stored until it is excreted through the urethra. The excretory system plays a crucial role in maintaining homeostasis by regulating the volume and composition of body fluids. Understanding this system is essential for recognizing how the body eliminates toxins and manages hydration, making the option associated with the excretory system the correct choice in this context.