Which organelle was a prokaryote:

Explanation

The mitochondrion and the chloroplast are both organelles that were once free-living cells. They were prokaryotes that ended up inside other cells (host cells). They may have joined the other cell by being eaten (a process called phagocytosis), or perhaps they were parasites of that host cell. Rather than being digested by or killing the host cell, the inner cell survived, and together they thrived. It's kind of like a landlord and a tenant. The host cell provides a comfortable, safe place to live and the organelle pays rent by making energy that the host cell can use. This happened a long time ago, and over time the organelle and the host cell have evolved together. Now one could not exist without the other. Today they function as a single organism, but we can still find evidence of the free-living past of the organelles if we look closely.