Which criterion is primarily used to distinguish between a Crab and an Earthworm at the 'basis of classification' level?
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Correct answer: Jointed legs present
While both have organ systems and are bilateral coelomates, jointed appendages are the defining characteristic of Arthropods (Crab), whereas Earthworms (Annelids) lack them.
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More Basis of Animal Classification questions
- Which of the following levels of organization is characterized by cells arranged as loose cell aggregates without forming tissues?
- In which phylum do cells performing the same function arrange into tissues for the first time?
- Animals in which the cells are arranged in two embryonic layers, an external ectoderm and an internal endoderm, are called:
- An undifferentiated layer, mesoglea, is present in between the ectoderm and the endoderm in:
- Radial symmetry is observed in which of the following phyla?
- When the body can be divided into identical left and right halves in only one plane, the symmetry is called: