Which phylum is known for having spicules?

• A. Porifera
• B. Cnidaria
• C. Annelida
• D. Mollusca

Answer: (A)

Spicules are tiny skeletal elements that give support and shape to sponge bodies, helping them stay rigid while maintaining their porous, water-pumping structure. In sponges, these spicules can be made of silica or calcium carbonate, and sometimes they are reinforced by spongin protein. This skeletal feature is distinctive to the phylum Porifera, whereas the other groups build with different tissues and organs and do not rely on spicules for their support. So recognizing spicules points to sponges.