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Hello lovely friends!
Last Sunday, my youngest and I went to our garden to plant a banana tree. When I dug a hole in the ground I lifted a lot of earthworms. The youngest is curious. He took the worm and placed it in his palm. When worm on the palms move his body shuddered, a sign of disgust.

"Dad, why is this worm always wet and mucusy?"

The youngest asked after I finished planting the banana tree.
"Let's go home later I'll explain so you understand."

Finally I explained why the worm is always wet and slimy to the youngest so he can understand it.

Respiratory organs

Every living thing must breathe. to do breathing requires certain breathing organs. Like mammal, birds, reptiles use the lungs. Fish use gills and insect use the trachea.
In the respiratory organ worm is the skin. This is unique. Unlike humans who breathe through the lungs, worms breathe through their skin like earthworms do.
Earthworms are the most common type of worms. As the name implies, this invertebrate animal lives in the soil.

Maybe many will ask why the skin on worms can become a respiratory organ?

Well, on the surface of the worm's skin there is a thin layer called the cuticle. Through the cuticle of the earthworm breathe.

Maybe there will be another question why is the skin of worms that have cuticles always wet?

Breathing means breathing in oxygen for use in the body. Oxygen in the soil cannot be directly absorbed by the skin. This oxygen must first be dissolved in water. The water in the mucus in worms makes the body always wet. The cuticle worms are always damp and wet. This layer can "absorb" air (oxygen) in the soil so that it enters the blood vessels of the worms. After entering the blood vessels, oxygen is circulated throughout the body.

Environmental Adaptation

Maybe someone will ask further.
Why do earthworms breathe through the skin?

Every living creature will adapt. Earthworm habitat is in the soil. Therefore, breathing through the surface of the skin is much better compared to special respiratory systems such as gills, lungs, and trachea.
By using the skin as a respiratory organ, oxygen can directly enter the blood vessels.

Thus my writing this time about the skin of earthworms that are always wet may be useful for us all.

Thank you for reading my post. I hope you enjoy it.