Fungi form a large group among the eukaryotes. Many people know fungi and their fruiting bodies as "mushrooms". The biggest difference to plants is that they are not able to perform photosynthesis, but mainly use the remains of other organisms as a source of energy. The two groups also differ greatly in their structure, as the fungus does not have roots, but a so-called fungal mycelium that grows through the subsoil in a net-like manner. An extremely important function of some fungi in nature is to break down old wood. Furthermore, there are fungi that colonize our food as mold and even fungi that colonize other organisms.
Explanation for children:
Fungi are a huge group among the eukaryotes. Some of them can be eaten, but there are many more. Many people know fungi and their fruiting bodies as "mushrooms". Some people think that fungi belong to plants, but this is not true, because fungi cannot photosynthesize. Instead, they use the remains of other organisms and are therefore really useful. Another important difference between plants and fungi is that fungi do not have roots, but fungal filaments. They grow through the underground and search for food. The fungal filaments are very strong and can break down almost anything, sometimes even wood.