Explanation:

- Option 1: Protoplasmic - This level is the simplest organization found in unicellular organisms, where functions are carried out within a single cell.

- Option 2: Cell-tissue - This involves the aggregation of cells that perform a similar function. It represents a level higher than the cellular organization.

- Option 3: Cellular - In this organization, cells are specialized but not organized into true tissues. They work collaboratively in some simple organisms.

- Option 4: Tissue-organ - In this grade of organization, tissues are organized into organs, with specialized functions. Animals in the phylum Platyhelminthes, like flatworms, show this level of complexity.