Answer: Organelle
Explanation:
Level of organization in living organisms refers to the increase in complexity of organisms. The increase in complexity is in structure, function, activity, behaviour and mode of life.There is an increase in Complexity from Unicellular organism to multicellular organism.The level of complexity in organisms both in unicellular and multicellular starting from the smallest to the largest are;
Elements
Molecules
Organelles
Cells
Tissues
Organs
Systems
(The) Organism
