Question

which reason best explains why dead specimens must be used with transmission electron microscopes?
○ electrons pass over the specimen.
○ the lights that are used are harmful to the specimens.
○ specimens are placed in a vacuum.
○ the image that is produced is two dimensional.

Explanation:

Transmission electron microscopes (TEM) require a vacuum environment. Living specimens can't survive in a vacuum (no air, pressure, or necessary gases for life), so dead specimens are used. Other options: electrons passing over (describes scanning EM), light harm (TEM uses electrons, not light), 2D image (doesn't relate to specimen being dead).

Answer:

C. Specimens are placed in a vacuum.