What preparation step is typically necessary for biological samples in most electron microscopy, limiting observation of living processes?

Answer

Samples must be chemically fixed, dehydrated, and prepared in a vacuum.

Because the electron beam scatters in air, most samples must be prepared in a vacuum, which requires them to be chemically fixed and dehydrated, preventing the observation of dynamic processes in living systems.

What preparation step is typically necessary for biological samples in most electron microscopy, limiting observation of living processes?
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