Which part of the turtle is the shell?

There are more than 285 kinds of turtles in the world, such as turtles, crocodiles, turtles and so on. They all have turtle shells, which are completely inseparable. The tortoise's shell is actually its skeleton, which is a structure in which the carapace and the spine are fused together. The tortoise shell is box-shaped, which can give good support and protection to the body, and at the same time ensure that the head, neck, limbs and tail can stretch freely. The outermost layer of tortoise shell consists of multiple bone plates, and each tortoise shell has 5/kloc-0 ossified bone plate.

In 2008, archaeologists in China discovered for the first time that turtle shells evolved from ribs, which broke the debate in biology for more than 200 years, because some paleontologists thought that turtle shells were skin bones similar to the surface armor of lizards. Later, some scientists discovered the "turtle ancestor" fossil, which further proved the conclusion of archaeologists in China and restored the formation process of turtle shells. The tortoise's shell is very smooth, so it can swim freely in the sea. Turtles can't hide their heads in shells like other turtles.

The turtle's eyes and face are transparent, just like goggles, which enables it to see around clearly under water. Turtles can eat jellyfish without being hurt by them.