The correct statements are:
• Some fungi can grow as either filamentous or single-celled forms.
Fungi are kingdom of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as macroorganisms mushrooms that contain chitin in their cell wall. Thus, fungus vary in form and shape.
• Mycelia are made up of small-diameter hyphae that form an interwoven mass, providing more surface area for nutrient absorption.
Most fungi are made of hyphae-long filamentous structure that can fuse and connect via anastomosis and form mycelium. They can increase their surface for nutrient absorption with structures such as haustoria and arbuscules.
• All fungi are heterotrophs; some species live as decomposers and others as symbionts
Fungi are like animals, heterotroph, meaning that none of them produce their own food like plants in photosynthesis. Fungi can be decomposers, parasites or symbionts
• Some fungi secrete digestive enzymes into the environment and then absorb the digested nutrients
This is also an example of their heterotrophic nutrition (obtain carbon and nutrients from other organisms or other sources, but not by their own production).