* Organelles are incredibly small: Organelles are structures within cells, and cells themselves are microscopic.

* Light microscopes have limitations: While light microscopes are great for viewing whole cells and some larger structures, they lack the resolution to see the fine details of organelles.

* TEM uses electrons: TEMs use a beam of electrons to create an image. Electrons have a much shorter wavelength than light, allowing for much higher resolution, making it possible to see the intricate details of organelles.

In summary: A TEM is necessary for viewing organelles due to their small size and the need for extremely high resolution imaging.