Question

how do prokaryotic cells most commonly differ from eukaryotic cells?

lack a nucleus

not multicellular

simpler metabolism

contain mitochondria

Explanation:

To determine the main difference between prokaryotic and eukaryotic cells, we analyze each option:

• "Lack a nucleus": Prokaryotic cells have no membrane - bound nucleus (their genetic material is in a nucleoid), while eukaryotic cells have a true nucleus. This is a fundamental and most common difference.
• "Not multicellular": Some prokaryotes can form colonies, and the key difference is not about multicellularity (many eukaryotes are unicellular too, like yeast).
• "Simpler metabolism": Metabolism complexity varies and is not the most defining difference.
• "Contain mitochondria": Prokaryotic cells lack membrane - bound organelles like mitochondria, while eukaryotic cells have them. So this option is incorrect.

Answer:

A. Lack a nucleus