Answer: Fungi
Explanation:
Organisms with the capacity to breathe anaerobically and aerobically are typically called obligate anaerobes. Obligate anaerobes are usually microorganisms- microscopic organisms.
Since the organism described is land-dwelling, chitinous and eukaryotic (containing a plasma membrane enveloped nucleus), they are most likely fungi. Chitin is a rigid, non-soluble carbohydrate utilized for structural purposes. Typically these organisms have strong, insoluble cell walls, are multi-cellular and can form filamentous networks of hyphae.
They create a tangled network of mycelia and may be:
