The phylum of radiata you will be observing today are the

Cnidaria

Cnidarian can also be refers to as Coelenterate and belong to the phylum Cnidaria. They share several attributes and this support the theory that they had a single origin. Cnidarian distinguish feature is the presence of Cnidocyte, a specialized cell that is being used mainly for capturing prey. The Cnidarians include jellyfish, Sea whips hydras, corals, sea pens etc.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

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