What are the two main types of electron microscopy and what are their pros and cons?

TEM (transmission electron microscopy): used to study ultra thin sections (< 100 nm) and can visualise the internal structures of cells. only samples with a limited thickness can be used and only 2D images can be generated. SEM (scanning electron microscopy): used to study the surface of solid, thick sections or objects. with this 3D images can be generated, but no internal structures can be visualised. sample preparation is also more complex.