Question

What are the spicules of poriferan animals made up of

Answer 1

Dear student,
Poriferas are commonly called sponges.These are multicellular organisms which are sessile in nature. The spicules of porifera are made up of either calcium carbonate or colloial silica. Accordingly, spicules are of two types:
1) CALCAREOUS SPICULES: The organic material in this type of spicules is calcium carbonate or calcite.
2) SILICEOUS SPICULES: The organic material in this type of spicules is colloidal silica or silicon.
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