Final answer:
Amoeba, which are eukaryotic unicellular organisms in the Amoebozoa supergroup, move using pseudopodia and ingest food by endocytosis, distinguishing them from the prokaryotic actinobacteria which lack these characteristics and have a fundamentally different form of cellular structure and movement.
Step-by-step explanation:
The feature that distinguishes amoeba from actinobacteria is their cellular organization and movement. Amoeba, part of the Amoebozoa supergroup, are eukaryotic unicellular organisms that move using pseudopodia, facilitated by actin microfilaments, allowing them to engulf food through a process called endocytosis. On the other hand, actinobacteria belong to the prokaryotic realm and exhibit a different form of cellular structure and, typically, a non-amoeboid movement.
Actinobacteria, as rod-shaped anaerobics, show adiverse metabolic capacity and can be found in both terrestrial and aquatic environments. In contrast, amoebas are well-known for their adaptability in freshwater sources and for sometimes being pathogenic to humans – for example, E. histolytica causing amoebic dysentery or Naegleria fowleri known as the "brain-eating amoeba."
While protists like amoeba can be motile, planctomycetes and other bacteria such as those from the CFB group, reproduce differently from amoebas and lack their complex cellular structures tailored for movement and food intake.