Explanation:
D
Sponges belong to the phylum porifera. Body wall is diploblastic, middle layer is called mesenchyme, which has various kinds of wandering amoebocytes. Body wall contains numerous pores called ostia through which water enters into the body and leads to canal system.
- Having no digestive system, Sponges are holozoic creatures. The choanocytes found in the flagellated chamber of the canal system which assist the food particles to be immediately absorbed.
- In sponges, sexual reproduction takes place through the participation of sperm and ovum.
- Since there is a continuous flow of water because of the canal system, the gaseous exchange takes place between cells of sponges and the flowing water.