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🔬 Biology  ·  Animal Kingdom  ·  NEET

Which of the following animals lacks separate sexes (is hermaphroditic)?

Answer: Earthworm (Pheretima).

  • A Ascaris, a parasitic roundworm species
  • B Earthworm (Pheretima)
  • C Periplaneta, the common cockroach
  • D Asterias, a marine starfish species

Correct answer: B. Earthworm (Pheretima)

Explanation: Earthworms are hermaphrodites, possessing both male and female reproductive organs in the same individual, though cross-fertilization is the norm.

Body Plan Progression Across PhylaPoriferaasymmetricalcellular levelCnidariaradial, diploblastictissue levelPlatyhelminthesbilateral, acoelomateorgan levelNematodapseudocoel.Annelida+true coelomorgan systemEach step adds organisational complexity: symmetry → germ layers → coelom type → organ systems

Moving across the animal phyla, body organisation becomes progressively more complex: from no symmetry and cellular organisation (Porifera) through radial/diploblastic (Cnidaria), bilateral/acoelomate (Platyhelminthes), pseudocoelomate (Nematoda), to a true coelom with full organ systems (Annelida and beyond).

Concept context

Phylum-level classification of the animal kingdom from Porifera to Chordata, based on body symmetry, coelom, and segmentation. One of the most example-heavy chapters for NEET.

Read the full Animal Kingdom notes →