Earthworm

- The earthworm is an organism that does not have bones.
- Instead of bones, earthworms have a long, cylindrical body made up of segments called annuli.
- These annuli are filled with fluid and act as a hydrostatic skeleton, providing support and allowing the earthworm to move.
- The annuli also have muscles that help in locomotion.
- Earthworms are classified as invertebrates because they do not have a backbone or a skeleton made of bones.

Tiger, Fish, and Bird

- On the other hand, tigers, fish, and birds are all organisms that have bones.
- Tigers belong to the category of vertebrates, which means they have a backbone and an internal skeleton made up of bones.
- Fish also have an internal skeleton made up of bones, which provides support and protection for their bodies.
- Birds, like tigers, are vertebrates and have a skeleton made up of bones.
- The bones in birds are specially adapted for flight, with hollow spaces to reduce weight and make it easier for them to fly.

Importance of Bones

- Bones serve many important functions in organisms that have them.
- They provide support and structure to the body, allowing organisms to maintain their shape and move.
- Bones also protect vital organs, such as the brain and heart, from injury.
- Additionally, bones are involved in the production of blood cells and the storage of minerals, such as calcium and phosphorus.

Conclusion

In summary, the earthworm is the organism among the options given that does not have bones. Earthworms have a hydrostatic skeleton made up of fluid-filled annuli, which provides support and allows them to move. On the other hand, tigers, fish, and birds all have skeletons made up of bones, which serve important functions such as support, protection, and blood cell production.

Fish and Bird are vertebrates so they have bones and the Cockroch is an insect but has external hard coverinf which is known as exoskeleton. SO the answer is C earthworm with no skeleton or bones.