Question

Which of the following groups consists exclusively of Cnidarians?
a) Aplysia, Gorgonia, Spongilla, Hydra b) Hydra, pennatula, Obelia, Echinus c) Hydra, Obelia, Adamsia, Physalia
Adamsia, Physalia

Answer 1

Answer:Solution

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Correct option is

A

i-d, ii-b, iii-c, iv-a

(i) Physalia is also know as Portugues man

of war is a marine hydrozoan found in  

the Athantic, Indian and Pacific oceans.

(ii) Meandrina is a genus of colonial stony croals

in the family meadrinidae.

(iii) Gorgonia is a genus of soft corals, sea fans

in the family Gorgoniidae.

(iv) Adamsia is a genus of sea anemones in the  

family tlormathiidae.

i−d,ii−b,iii−c,iv−a  

Explanation:

Answer 2

Of the following groups c) Hydra, Obelia, Adamsia, Physalia consists exclusively of Cnidarians

• Among the following given options only Hydra, Obelia, Adamsia, Physalia consists exclusively of Cnidarians as these organisms can be characterized by the presence of tentacles on their bodies.
• Members of this phylum are diploblastic.
• Their digestion can be intracellular or extracellular.
• These organisms posses a single mouth opening called a hypostome.
• Hydra, Adamsia and Physalia have sessile body.
• Obelia possess Metagenesis as it can reproduce in either of the ways.