<span>They exhibit all the stages when its the presence of oxygen only.</span>
Answer: Coelenterates as a whole are of little economic importance. Seldom used as food by man, they are eagerly devoured by certain fishes and by invertebrates such as the crown of thorns starfish. Certain corals used as ornaments and for the manufacture of jewelry have become rare because of exploitation.
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<em>Hope it will help you !</em></u></h2>
<span>The location in which a person is more likely to receive an echo of the soud being sent is at least 16.6. meters in front of the reflecting surface. Therefore, the answer is to this item is letter A. The speed of sound without any interference is only about 340 m/s traveling through the vibration of the media in which it passes through. </span>