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Earthworms live in different strata of the soil. Earthworms occur in diverse habitats that vary in size and feed on live and dead organic materials. Earthworms are burrowing animals that feed on dead organic matter, living bacteria, fungi and other microorganisms.
 
Earthworms do not have lungs, and it breathes through the skin. The exchange of gases keeps the outermost layers moist through mucus excretion onto the skin.
 
Earthworms play a vital role in maintaining soil fertility. Earthworms facilitate soil aeration, water infiltration, and organic matter that acts as hummus, facilitating crops' growth.
 
The adaptations that are present in earthworms include:
 
1. Streamlined body:
 
The earthworm has a cylindrical, elongated, segmented body made of many ring-like segments called the annuli.
 
800px-Earthworm_segments_Labeled_Segments.jpg
Earthworm
 
It has a streamlined body with no fins, antennae, arms or legs. The streamlined shape of the body helps it live in narrow, underground burrows. The body is also useful for easy penetration into the soil.
 
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Streamlined body of an earthworm
 
2. Skin:
 
Slimy mucus is excreted by the earthworm that covers the skin. This does not allow the soil particles to stick to the earthworm's body. The moist skin also helps in the oxygenation of blood. It is required for oxygen to be absorbed and carbon dioxide to be given off.
 
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Exchange of oxygen and carbon dioxide through the skin
Reference:
https://commons.wikimedia.org/wiki/File:Earthworm_segments_Labeled_Segments.jpg
https://pixabay.com/photos/worm-earthworm-annelid-belt-worm-4763219/
https://www.yaclass.in/p/science-cbse/class-7/respiration-in-organisms-8451/re-bbe57d29-e96d-4fe8-82ad-b992236abd14