Answer:
A predatory or parasitic relationship
Step-by-step explanation:
According to the endosymbiotic theory, the larger prokaryotic cell may have been predating on the smaller prokaryotic cell, before a mutual relationship developed later on. Another hypothesis is that it was probably a parasitic relationship. Over time, the phagocytosed cell survived inside the larger cell and a symbiotic relationship developed over time because it provided an evolutionary advantage.