Summary table at the end of the chapter. Identify phylum and identifying characteristics: 31. 12, 31. 16, 31. 18. Concept 31. 1 fungi are heterotrophs that feed by absorption. Feed by absorbing nutrients from the environment. Done by: secreting hydrolytic enzymes into their surroundings that break down complex molecules to usable simple compounds, enzymes to penetrate walls of cells enabling the fungi to absorb nutrients faster. Decomposer fungi absorb nutrients from dead organisms. Parasitic fungi absorb nutrients from the cells of living hosts. Mutualistic fungi absorb nutrients from the cells of living hosts, but in a way that benefits the host as well. Multicellular filaments or single celled: many species an grow as both. Morphology of multicellular enhance their ability to grow into and absorb nutrients. Bodies typically form hyphae: hyphae: one of many connected filaments that collectively make up the mycelium of a fungus, consists of tubular walls surrounding the plasma membrane and cytoplasm.