Complex sentence: Electron microscopy or atomic force microscopy reveals the pits to be an elaborate net-like structure called a reticulum, with two to three pores per micrometer, each approximately 400 nanometers deep.
Split into simpler sentences: Electron microscopy or atomic force microscopy reveals the pits, or pores, to be an elaborate net-like structure called a reticulum. There are two to three such pores per micrometer, each approximately 400 nanometers deep.