In Vertebrates, the embryonic notochord is replaced by a bony or cartilaginous vertebral column in adults (b is TRUE). Chordates characteristically possess a single dorsal, hollow nerve cord (c is TRUE). Statement (a) confuses Urochordata with Cephalochordata, and (d) treats Hemichordata as a subphylum. (b) and (c) are the only true statements! Select Option (4).
1 Check Statement (a): In Urochordata (Tunicata), notochord is present ONLY in larval tail; in Cephalochordata it extends head-to-tail throughout life. Statement (a) is FALSE.
2 Check Statement (b): In Vertebrata, notochord exists during embryonic stages and is replaced by a vertebral column in adults. Statement (b) is TRUE.
3 Check Statement (c): Chordates possess a dorsal, hollow, single central nervous system. Statement (c) is TRUE.
4 Check Statement (d): Chordata is divided into Urochordata, Cephalochordata, and Vertebrata (Hemichordata is a separate non-chordate phylum). Statement (d) is FALSE.
5 True statements: (b) and (c) -> Select Option (4).
🛡️ Why You Can 100% Trust This Shortcut: NCERT Biology · Animal Kingdom (Phylum Chordata: Central nervous system is dorsal, hollow and single. In subphylum Urochordata, notochord is present only in larval tail, while in Cephalochordata, it extends from head to tail region and is persistent throughout their life. The members of subphylum Vertebrata possess notochord during the embryonic period; the notochord is replaced by a cartilaginous or bony vertebral column in the adult).
