Final answer:
The organelle that all eukaryotes have in common is the nucleus, which is surrounded by a membrane.
Step-by-step explanation:
Eukaryotic cells, unlike prokaryotic cells, have a membrane-bound nucleus and numerous membrane-bound organelles. These organelles, such as the endoplasmic reticulum, Golgi apparatus, chloroplasts, and mitochondria, perform specialized cellular functions. The main difference between eukaryotes and prokaryotes lies in the presence of the nucleus, as it is surrounded by a membrane and often referred to as a 'true nucleus.'
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