Question

sponge knowledge check
sponge skeletons also have hard fibers called ​__________ composed of calcium carbonate or silicon dioxide.
○ spicules
○ porocytes
○ spongin
○ amoebocytes

Explanation:

Sponge skeletons have hard fibers. Spicules are made of calcium carbonate or silicon dioxide. Porocytes are for water flow. Spongin is a protein. Amoebocytes have other functions.

Answer:

spicules