Final answer:
The mycelium's large surface area is vital for nutrient absorption because it efficiently receives nutrients from the environment through its expansive network of hyphae.
Step-by-step explanation:
The large surface area of the mycelium is essential for nutrient acquisition by fungi because it facilitates the absorption of nutrients from the environment. The mycelium, consisting of a network of hyphae, has a high surface-area-to-volume ratio, which allows for efficient absorption of nutrients. Fungi are heterotrophs and they digest nutrients by releasing enzymes into the environment that break down large organic molecules into smaller molecules that are easily absorbed. Some fungi have specialized structures that penetrate into host cells to obtain nutrients directly.