An undergraduate student is preparing various eukaryotic tissue samples to compare their structures using both light microscopy and electron microscopy. Which of the following statements about specimen preparation and imaging principles is not correct?
In transmission electron microscopy (TEM), specimens must be cut into extremely thin sections (typically less than 100 nm100\text{ nm}100 nm) using an ultramicrotome because the electron beam has very low penetrating power.
In scanning electron microscopy (SEM), the electron beam is focused across the specimen's surface, and secondary electrons knocked off the surface are detected to produce a detailed three-dimensional image.
Light microscopes can be used to observe living specimens because they do not require a vacuum, whereas both TEM and SEM require a high vacuum, meaning only dead or dehydrated specimens can be imaged.
Because scanning electron microscopy (SEM) has a lower resolving power than transmission electron microscopy (TEM), specimens do not need to undergo dehydration or metal coating before being placed in the vacuum chamber.
