Small, needle-like structures found in living organisms, such as sponges or radiolarians.
Spicules are tiny and pointy, and they help living things keep their shape and structure.
Examples:
The sponge is made of tiny spicules.
The radiolarians have spicules in their bodies.
The spicules help the sponge stay strong.
The spicules look like little needles.
The sponge is full of spicules, like a porcupine.
The spicules are so small, you need a microscope to see them.