system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does the human body expel waste through urine and lose water? Couldn't the waste product in urine just be expelled in feces and keep the water?
gpt
Faeces and urine have two different sources. The former is the remnants of the food we've eaten after all the useful stuff has been extracted from it, including water. Urine, on the other hand, is the result of your kidneys filtering stuff out of your bloodstream that shouldn't be there. Since the blood is fluid the results of filtering it are also somewhat fluid--it's not really possible to completely remove all the dry stuff and leave the fluid behind, because doing that would clog up your filter really quickly.