My question is very specific. If the Earth had evolved to never have animals, and instead only have plants and fungi, could the Earth be habitable for humans, or any life at all? Could it be breathable for us? And could the plants and fungi evolve to the point where they can move on their own, have brains, and even eat?
I thought of this idea one night when I was thinking of alternate realities, and wondered if this was possible. Please, I need to know if this is even somewhat plausible. To be even more specific, the plants would still do photosynthesis, as we know they do, but the fungi would have to eat like us. Is this possible or even plausible?