What process involves one organism living inside another, leading to the incorporation of cellular functions, such as the origin of mitochondria?

Answer

Endosymbiosis.

Endosymbiosis is the process where one organism lives inside another, leading to incorporation of one cell within another, demonstrated by the evolution of eukaryotic cells through the engulfment of aerobic bacteria (mitochondria) and photosynthetic cyanobacteria (chloroplasts).

What process involves one organism living inside another, leading to the incorporation of cellular functions, such as the origin of mitochondria?
biologyevolutioninteractioncoevolutionsymbiosis