Prokaryotic Cell Size Range

Steps:

• Prokaryotes include bacteria and archaea, typically 0.1–5 μm in diameter.
• Most bacteria, the dominant prokaryotes, measure 0.2–2 μm, with many under 1 μm.
• Convert: 1 μm = 1000 nm, so 0.1 μm = 100 nm.
• Match to options: B (100 nm–1 μm) covers the smallest to typical sizes for most.

Why B is correct:

• Standard biology defines prokaryotic cell diameters as 0.1–1 μm for most species, directly aligning with B's range.

Why the others are wrong:

• A: 1–100 nm scale applies to viruses or organelles, not whole prokaryotic cells.
• C: 1–100 μm range fits eukaryotic cells; only rare prokaryotes (e.g., filaments) exceed 1 μm.
• D: 100 μm–1 mm is visible to the naked eye, far larger than any prokaryote.

Final answer: B