Develop some hypotheses explaining why only eukaryotic cells have evolved into multi-cellular organisms.

Prokaryotic cells are structurally simple. They are found only in single-celled and colonial organisms. Eukaryotic cells have organelles with their own membranes. Single-celled eukaryotic organisms are very diverse, but many colonial and multicellular forms also exist. The first of eukaryotic cells probably evolved or split off from Archeans, which have attributes of both prokaryotes (oxygen haters, e.g. bacteria), but also contain genes that are more like what you'd find in eukaryotes (oxygen lovers e.…

…called mitochondria that take care of respiration for the cell. These are endosymbionts like chloroplasts. Mitochondria formed this symbiotic relationship very early in eukaryotic history, all but a few groups of eukaryotic cells have mitochondria. Later, a few lineages picked up chloroplasts. Chloroplasts have multiple origins. Red algae picked up urchloroplasts from the cyanobacterial lineage. Green algae, the group plants evolved from, picked up different urchloroplasts from a prochlorophyte, a lineage closely related to cyanobacteria.