system
Given the following post, respond as if you're commenting on Reddit:
human
If every multicellular life form suddenly disappeared, would singled celled life forms eventually re-evolve into multicellular ones again?
gpt
Probably yes. The removal of multicellular life would not be a "reset to zero" event. There is still complex single cellular life, some of which is actually very closely related to multicellular life. A really good example would be baker's yeast.

There's at least three origins of multicellularity across eukaryotes between animals, plants and fungi, so if any Eukaryote survived it's actually quite reasonable to assume it could happen again. Since there's plenty of single celled eukaryotes there's pretty good odds that multicellular life would reemerge from them.

The reset to zero event would be the loss of all eukaryotic life. Whether multicellular life could recover from that is far less likely.