Neural Control and CoordinationMedium
Question
The following are the statements about non-chordates:
A. Pharynx is perforated by gill slits.
B. Notochord is absent.
C. Central nervous system is dorsal.
D. Heart is dorsal if present.
E. Post anal tail is absent.
Choose the most appropriate answer from the options given below:
Options
A.B, D & E only
B.B, C & D only
C.A & C only
D.A, B & D only
Solution
Sol. [Key Concept: Chordate and nonchordate comparison]
Using the standard NCERT comparison, B, D and E are the intended nonchordate features: no notochord, a dorsally positioned heart where present, and no postanal tail. Hence, option (1). These are broad comparative features rather than universal rules for every nonchordate phylum; hemichordates, for example, possess pharyngeal gill slits.
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