system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Ants: from where do these tiny little ones come out when you drop food? Why are they not visible otherwise? Why are they always in packs and unending line?
gpt
Most ants are underground in their nest (or some nest in trees). There are scouts who are looking for food.  When they find food/water they lay down a scent and then walk back to the nest.  All of the ants in the nest can then follow that scent all the way to the food.  They're all following that scent on the ground in the same line the scout took to get home from the food.