Answer:
The correct answer is - tissue.
Explanation:
In an unfavorable condition like scarcity of food, individual unicellular organism amoeba makes a formation a multicellular mass by aggregation of the cells that reproduce when conditions become favorable. These aggregation of cells known as slime molds.
These molds are more similar to the tissue structure in the hierarchy of organization of a multicellular organism. The tissue is the organization level that is similar to this mass as it is also formedby the cells joined together to perform a particular function.