Which of the following statements about phylum Cnidaria is correct?

Explanation

Phylum Cnidaria is a group of animals that includes jellyfish, corals, and sea anemones. The question is asking which of the following statements is correct about this group. The options are: A) They are diploblastic animals, B) Body is sac-shaped with three openings, C) They are bilaterally symmetrical, and D) They are triploblastic animals with two openings.The correct option is A, which states that they are diploblastic animals. Diploblastic means that the animals have two germ layers, the ectoderm and endoderm, which are separated by a gelatinous layer called mesoglea.Option B is incorrect because the body of Cnidarians is not sac-shaped with three openings; instead, it is characterized by radial symmetry, with a central mouth and tentacles surrounding it.Option C is also incorrect because Cnidarians are not bilaterally symmetrical. Bilateral symmetry means that an animal can be divided into two equal halves along a plane that runs from head to tail. However, Cnidarians cannot be divided into two equal halves in this way.Option D is also incorrect because Cnidarians are not triploblastic animals with two openings. Triploblastic means that an animal has three germ layers, the ectoderm, mesoderm, and endoderm, while having two openings refers to animals that have a mouth and an anus. However, Cnidarians have a single opening, which serves as both the mouth and anus.In summary, option A is the correct statement about phylum Cnidaria, which is that they are diploblastic animals.