Mushrooms are classified as fungi. Unlike plants, fungi do not perform photosynthesis; instead, they obtain nutrients through absorption. Fungi, including mushrooms, have a unique cellular structure, containing chitin in their cell walls, distinguishing them from plants and animals. They play essential roles in ecosystems as decomposers, breaking down organic matter and recycling nutrients back into the soil. Additionally, some mushrooms are edible, while others can be toxic, demonstrating the diversity within the fungi kingdom.