system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do dogs eat poop?

Why do dogs eat poop? Is there a biological reason?
gpt
A lot of animals don't have great digestive systems - most of the nutrients pass right through their body. In order to get those nutrients, the animal has to process the food more than once.

Some animals, like cows, barf up the food to chew it several times before swallowing again. Other animals, like rabbits, just eat their poop to get the nutrients they missed the first time around.

Dogs do both. People do neither.