In medusae, mesoglea comprises the bulk of the animal and forms a resilient skeleton. In polyps, the water-filled coelenteron acts as a hydrostatic skeleton, which, in concert with the mesoglea, maintains the form of these animals. Muscles in cnidarians are extensions of the bases of ectodermal and endodermal cells.
<span>Something that occurs outside the spheres of the earth
Consider that human beings or living organisms live in the biosphere. Biosphere is the collective group of living organisms and their interaction to one another and –ecosystem- to their environment. Human beings like animals or plants are part of the biosphere, one of the spheres in the earth. We have the atmosphere (air), lithosphere (land), hydrosphere (water) and the biosphere (life/ living organisms). Each is with a specific and distinctive characteristics to play in the earth’s existence at the current era.<span>
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Each layer has its own properties, composition, and characteristics that affects many of the key processes of our planet. They are, in order from the exterior to the interior – the crust, the mantle, the outer core, and the inner core.
Your answer is going to be D
