Final answer:
The amoeba used phagocytosis to consume its prey.
Step-by-step explanation:
The type of endocytosis that the amoeba you saw consuming its prey used is phagocytosis. Phagocytosis is a form of endocytosis in which the cell membrane surrounds and engulfs large particles, such as food, forming an intracellular vacuole called a phagosome. In the case of the amoeba consuming its prey, it extends pseudopodia to engulf the food particle and then forms a phagosome for digestion.
Learn more about Endocytosis