Why do mushrooms secrete a special kingdom in the organic world?

For a long time, scientists could not determine which kingdom the mushrooms belong to: either plants or animals.

As plants, they do not move, they grow at their top.

As animals, they do not have chlorophyll and they have to eat prepared food, that is, they are heterotrophs by the way of feeding, they are not capable of photosynthesis, like plants. They have a cell wall impregnated with chitin. The reserve substance is glycogen, like in animals.

But unlike plants and animals, fungi are composed of thin filaments – hyphae, which form the mycelium.