LL ANSWER
The transmission electron microscopef the specimen. Because the electrons of scanning electron microscope scan the surface rather than pass through a specimen, scanning microscopes can image much thicker specimens than a transmission electron microscope, even scanning whole organisms. Scanning electron microscopes yield three-dimensional images of arthropods and bacteria.
The major drawback of electron microscopes is their inability to study living organisms. Light microscopes yield excellent information on the movement of microorganisms, but the necessary vacuum of an electron microscope prevents the study of anything living. Also, transmission electron microscopes often require specimens to be in very thin sections.