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Biradial symmetry and lack of cnidoblasts are the characteristics of -
A
Starfish and sea anemone
B
Ctenoplana and Beroe
C
Aurelia and Paramecium
D
Hydra and starfish
Detailed Solution
Ctenophores, commonly known as sea walnuts or comb jellies, are exclusively marine, diploblastic animals with the tissue level of organisation.
Their symmetry is biradial: the body can be divided into two equal halves along only two planes.
They do not have cnidoblasts (stinging cells); instead their tentacles bear adhesive cells called colloblasts for capturing prey.
They have eight external rows of ciliated comb plates, which help in locomotion.
Ctenoplana and Beroe are both ctenophores.
Sea anemone, Aurelia and Hydra are cnidarians and possess cnidoblasts; starfish is an echinoderm and Paramecium is a protist.
So biradial symmetry and the lack of cnidoblasts are characteristics of Ctenoplana and Beroe.
Their symmetry is biradial: the body can be divided into two equal halves along only two planes.
They do not have cnidoblasts (stinging cells); instead their tentacles bear adhesive cells called colloblasts for capturing prey.
They have eight external rows of ciliated comb plates, which help in locomotion.
Ctenoplana and Beroe are both ctenophores.
Sea anemone, Aurelia and Hydra are cnidarians and possess cnidoblasts; starfish is an echinoderm and Paramecium is a protist.
So biradial symmetry and the lack of cnidoblasts are characteristics of Ctenoplana and Beroe.