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.
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.
Hold out your arm and look at your thumbnail: that's roughly the only area you see truly sharply, the part landing on your fovea, about 2 degrees of your visual field. Everything else is blurry and color-poor. Your brain assembles a crisp picture of the world by constantly moving your eyes.