Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason

Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). 
Assertion (A): All vertebrates are chordates but all chordates are not vertebrate. 
Reason (R): The members of subphylum vertebrata possess notochord during the embryonic period, the notochord is replaced by a cartilaginous or bony vertebral column in adults. 
In the light of the above statements, choose the correct answer from the options given below :

Professor PC Thomas Classes · Answer

(c) : Phylum Chordata possesses three sub-phylum (Urochordata, Cephalochordata, Vertebrata) which possess notochord at some stage of 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. Thus, all vertebrates are chordates but all chordates are not vertebrates.