The fungi are things like mushrooms and molds.
While many are considered icky, they are important to life as we know it.
Besides the everyday, well known fungi, there are many "invisible" fungi in the world around us. Some are too small to see without a microscope. Healthy soil is full of tiny, incredibly fragile, "threads" which are living things of the fungi kingdom.
Without fungi, human-kind would not have known leavened bread. Or beer, wine, spirits. Or penicillin.
On the other hand, athlete's foot, and other life threatening "diseases" are also due to fungi "eating" you.
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The "Fungus" group is one of the primary sub-divisions of all living things.