Answer:
Nucleus.
Step-by-step explanation:
The sponge is a multicellular organism that consists of pores that allows water to move through the body. Sponges belong to the kingdom Animalia and phylum Porifera. Sponges can reproduce by budding. Sponges are placed in kingdom Animalia because they are unable to make their own food, made of more than one cell, and absence of cell wall.