Spicules are best described as?

Spicules are best described as?

• A. Nerves
• B. Muscles
• C. Small, needle-like structures found in some sponges that provide structural support
• D. Pigment cells

Answer: (C)

Spicules are the rigid skeletal elements that give many sponges their shape and structural support. They’re usually tiny, needle-like particles made of silica or calcium carbonate that form a framework helping the sponge hold its form in moving water. Some sponges also have spongin, a flexible protein, but spicules provide the solid skeleton. Sponges lack true nerves and muscles, so those options don’t describe their biology, and pigment cells aren’t the defining feature here.

Spicules are the rigid skeletal elements that give many sponges their shape and structural support. They’re usually tiny, needle-like particles made of silica or calcium carbonate that form a framework helping the sponge hold its form in moving water. Some sponges also have spongin, a flexible protein, but spicules provide the solid skeleton. Sponges lack true nerves and muscles, so those options don’t describe their biology, and pigment cells aren’t the defining feature here.