Plants and fungi were once classified in a single kingdom. Which similarity between plants and fungi led to this classification? their photosynthetic energy acquisition
their nonmotile, fixed body structures
their decomposer role in ecosystems
their predation on bacteria

their nonmotile, fixed body structures

Explanation:

Fungi and plants are currently classified into two distinct kingdoms. However, due to some of their common observed features, they were once classified together as one kingdom. Fungi are a group of heterotrophic organisms that possess cell well while Plants are group of autotrophic organisms that also possess cell wall.

Previously, the observable similar features were the basis of classification of organisms. It was observed that fungi and plants were nonmotile i.e. cannot locomote, and possessed a fixed body structure that grew out of the soil (fungi mushroom).