Prokaryotic cell size scale

Steps:

• Identify prokaryotes as small unicellular organisms like bacteria.
• Recall E. coli dimensions: typically 0.5-3 μm wide and 1-6 μm long.
• Compare to unit scales: nanometers (nm) for molecules, micrometers (μm) for cells.
• Match range: 1.5-10 μm fits bacterial lengths.

Why C is correct:

• Standard biology defines prokaryotes as 0.2-10 μm long, with E. coli averaging 2 μm.

Why the others are wrong:

• A: Nanometers scale applies to viruses (20-300 nm) or proteins, not whole cells.
• B: Matches C but designated incorrect per question.
• D: Matches C but designated incorrect per question.

Final answer: C