Yes they are.
They are shaped like a tube!
Appendix
The trachea is a tube made of c-shaped rings of cartilage. This structure gives it flexible but strong support.
No - Ballistic missiles are ejected in an air bubble, using compressed air while the boat is at periscope depth. When the missile clears the water surface, its solid fuel rocket motor ignites, sending it on its way to the target. Cruise missiles can be launched by VLS (Vertical Launch System) tubes, or by standard torpedo tubes. Torpedo tube launches are performed by flooding the tube with water, and a piston ram system ejects the water and weapon out of the tube, where its motor ignites. VLS launches are similar to BM launches in that they are ejected by air pressure.
a axle
When magma rises and carves a tube-shaped structure, it forms a volcanic conduit or lava tube. These can serve as pathways for magma to travel from the magma chamber to the surface during volcanic eruptions.
It is shaped like a tube
cylindania
No.It has an oval shape I Guess
It is a cylinder (or could depend)
Lava tubes.