Answer:
Agar
Explanation:
In the given question, the substance obtained from a multi-cellular organism with its plant-like and stores starch like a plant is the algae.
Many useful substances are obtained from these algae whose characteristics are given are like they are jelly-like, used as food, used to grow the cultures of organism shows the properties of a chemical called agar.
Agar is obtained from the species of genus Gelidium and the Gracllaria red algae which are plant-like organisms.
Thus, agar is the correct answer.