The correct answer is option 4, Mitochondria. Mitochondria are cell organelles found in eukaryotic cells that are believed to have evolved through a process called endosymbiosis. Endosymbiosis is the theory that suggests that mitochondria were once free-living bacteria that were engulfed by a primitive eukaryotic cell. Over time, this engulfed bacteria formed a symbiotic relationship with the host cell, eventually becoming an integral part of it.

Option 1: Peroxisomes, on the other hand, are not acquired through the process of engulfment or endosymbiosis. They are formed through the division of pre-existing peroxisomes or by the incorporation of lipids and proteins from the endoplasmic reticulum.

Option 2: Vacuoles are membrane-bound organelles that are involved in various functions such as storage, digestion, and waste disposal. They are not acquired through the process of engulfment or endosymbiosis.

Option 3: Chloroplasts are organelles found in plant cells that are responsible for photosynthesis. Like mitochondria, they are also believed to have evolved through endosymbiosis, but they originated from an ancient engulfment of cyanobacteria and not