What is this close-up picture? (WotsThat: Cuttlefish bone interior)

Question

What object is shown in this zoomed-in close-up photo?

RustKnight · Accepted Answer

Cuttlefish bone interior. The inside of a cuttlefish bone is riddled with thousands of tiny gas-filled chambers arranged like a microscopic apartment building, which the cuttlefish can adjust by adding or removing gas to fine-tune its buoyancy and hover motionless in the water. This biological engineering is so efficient that the structure inspired human engineers designing submarines and aircraft, and the bone is so lightweight yet strong that people have been grinding it up for centuries to use as everything from toothpaste to chicken feed.

Answer: Cuttlefish bone interior

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