Answer:
Radial symmetry
Explanation:
One of the most prominent features of echinoderms is their radial symmetry. This means that if we divide the organism around any main axis it should be divided in two exactly similar halves across any plane passing through the body. This is because the mouth is surrounded by a central disk that contain specific structures called podia that radiate outwards and gives the radial symmetry to organism.
For example: The body of ctenophores, echinoderm, sea-anemone and many sponges have radial symmetry. Some echinoderms that have radial symmetry include sea urchin, Sea cucumber, bitter star etc.
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The first line of barrier that support the immune system by the invading microorganisms is formed by the skin and the mucous membrane.
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What is immune system?</h3>
A network of biological processes called the immune system guards an organism against disease.
<h3>How do skin and mucous membrane support the immune system?</h3>
The skin acts as the first line of defense and has specialized immune cells that help prevent the microorganisms from entering the body.
The mucous membrane which is more sensitive and lines up the internal organs of the body can sense and eliminate the microorganisms thus helping the immune system.
Learn more about the immune system with the help of the given link:
brainly.com/question/13257880
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Steel is magnetic, aluminium is not. So the electro magnet would pull only the stell food cans, separating them.
Answer:

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