Fungi are a diverse group of organisms that include mushrooms, molds, and yeasts. They play a crucial role in nature by breaking down dead organic matter, which helps recycle nutrients back into the soil. Unlike plants, fungi do not perform photosynthesis; instead, they absorb nutrients from their surroundings through their cell walls. Many fungi are beneficial to humans. For example, yeast is used in baking and brewing, while certain mushrooms are enjoyed as food. Additionally, some fungi produce antibiotics, like penicillin, which have saved countless lives. Overall, fungi are essential for both ecosystems and human activities.