Question

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Members of subphylum vertebrates possess notochord during the embryonic period. The notochord is replaced by a cartilaginous or bony vertebral column in the adult.
Reason R: Thus all chordates are vertebrates not all vertebrates are chordates.
In the light of the above statements choose the correct answer from the option given below

• A. A is true but R is false.
• B. A is false but R is true
• C. Both A and R are true and R is the correct explanation of A.
• D. Both A and R are true but R is NOT the correct explanation of A.

Answer 1

The Correct Option is A

The given question consists of an Assertion and a Reason related to the subphylum vertebrates. Let's evaluate each statement:

1. Assertion (A): Members of subphylum vertebrates possess a notochord during the embryonic period. The notochord is replaced by a cartilaginous or bony vertebral column in the adult.
   • Explanation: In vertebrates, the notochord is present during the embryonic stage. As the organism develops, the notochord is typically replaced by a vertebral column made of bone or cartilage. This is a fundamental characteristic of vertebrates.
   • Conclusion: The assertion is true.
2. Reason (R): Thus all chordates are vertebrates not all vertebrates are chordates.
   • Explanation: The phylum Chordata includes all animals that possess a notochord at some stage of their life. Vertebrates are a subgroup within Chordata that have a developed vertebral column. While all vertebrates are chordates (having a notochord at some stage), not all chordates are vertebrates (as some chordates do not develop a full vertebral column).
   • Conclusion: The reason is false because the correct statement should be "All vertebrates are chordates, but not all chordates are vertebrates."

Thus, based on the evaluations:

• The correct answer is: A is true but R is false.