Answer:
The correct answer would be - smaller and ultra-thin structures than a cell.
Explanation:
TEM or the transmission electron microscope is one of an electron microscopy technique that forms an image from a specimen in which electron passes through a substance.
TEM is used to study the specimen that is ultra-thin to be precise it should be less than 100 nm smaller specimen section such as sections or structure smaller than a cell.
Thus, the correct answer is -smaller and ultra-thin structures than the cell.