At one time, biologists thought that fungi were merely forms of plants that had lost their chlorophyll and had returned to saprotrophy to gain food. Why is this no longer considered a solid theory?
A) Fungal cell walls contain chitin rather than cellulose.
B) Fungi attack and engulf food for internal digestion.
C) Fungi have flagella at some stage, providing mobility that plants never have.
D) Plants are multicellular and fungi are unicellular or multinucleated noncellular plasmodia.
E) All of these are differences between fungi and plants.