How many kidneys do humans have?

Humans have two kidneys, which are vital organs responsible for filtering waste products from the blood and regulating fluid balance in the body. Each kidney contains approximately one million filtering units called nephrons. This dual kidney system ensures that if one kidney is damaged or fails, the other can often take over much of the workload, maintaining sufficient function. Having two kidneys contributes to the body's efficiency in processing waste and balancing electrolytes, which is crucial for maintaining overall homeostasis. The presence of two kidneys is a characteristic of human anatomy and provides a functional redundancy that can be beneficial for survival.