Final answer:
An electron microscope, including TEM and SEM types, requires drying of specimens smaller than 0.2 micrometers before examination, due to the need for a vacuum environment and high magnification capabilities. For thick samples, such as biofilms, a confocal scanning laser microscope is ideal.
Step-by-step explanation:
The type of microscope that requires specimens smaller than 0.2 micrometers to be dried before study is an electron microscope. There are two main types of electron microscopes: the transmission electron microscope (TEM) and the scanning electron microscope (SEM). The TEM requires thin samples that can be viewed in a vacuum to examine very small details, while the SEM is used to view surfaces and can handle somewhat thicker samples. When it comes to viewing thick structures, such as biofilms, the best choice would be a confocal scanning laser microscope, which allows for high-resolution imaging of thicker samples by focusing a laser through the specimen and capturing the emitted light through a pinhole aperture. On the other hand, a brightfield microscope with or without a stain, as well as a darkfield microscope or a phase-contrast microscope, are more suitable for samples that do not require the high levels of magnification provided by electron microscopy.