Some scientists hypothesize that the eukaryotic cells are really the result of symbiotic processes!
Specifically, the internal organs of the cells could be a remnant of a symbiotic relationship in which one cell lived inside of another cell. These two cells then both split upon reproduction and eventually the cell inside was reduced to an organelle.
But according to this theory, it is very likely that the prokaryotic cells engaged in a number of symbiotic relationship, and that this actually lead to the emergence of eukaryotic cells! <span />
You see jellyfish adapted to not having a brain but they still have a nervous system. This nervous system goes to there tentacles which helpes jellyfish detect tempatures, touch, food etc.
If that did help i would gladly accept brainliest thanks duded and have a great day!