For this technique, which section thickness is specified?

• A. 1-2 nm
• B. 5-10 µm
• C. 10-20 µm
• D. 0.5-1 µm

Answer: (A)

Electron microscopy relies on electrons passing through the specimen, so the sections must be extremely thin to minimize scattering and allow a clear image. The only option in the nanometer range achieves this ultrathin requirement, making it suitable for TEM imaging. Thick micrometer-scale sections would block or heavily scatter electrons, yielding little to no usable image. Therefore, specifying a nanometer-thick section best fits the needs of this technique.