In each of your cells, DNA suffers somewhere between 10,000 and 100,000 lesions a day: heat, oxygen, radiation and spontaneous chemical errors. Teams of enzymes patrol constantly to detect and fix the damage. Without them, your genome would fall apart. Their discovery earned the 2015 Nobel Prize in Chemistry.
Every day, your kidneys filter around 180 liters of blood plasma, about a bathtub's worth. Yet you only have about 3 liters of plasma, so it passes through your kidneys some sixty times a day. Over 99% of the filtered water is reabsorbed, leaving just one to two liters of urine.
A 70 kg adult is made of about 7 × 10²⁷ atoms, or seven billion billion billion. The observable universe is thought to hold on the order of 10²² to 10²⁴ stars. Even with the high estimate, you contain thousands of times more atoms than there are stars in the entire visible cosmos.