Assertion A is correct. Vertebrates possess a notochord during embryonic development, which is later replaced by a vertebral column.
Reason R is incorrect. All vertebrates are chordates, but not all chordates are vertebrates (e.g., tunicates, cephalochordates). The presence of a notochord at some stage in development is a defining characteristic of chordates. The relationship between chordates and vertebrates is not accurately described in R.

| List - I | List – II | ||
| A. | Lemur | i. | Flying phalanger |
| B. | Bobcat | ii. | Numbat |
| C. | Anteater | iii. | Spotted cuscus |
| D. | Flying squirrels | iv. | Tasmanian tiger cat |
Given below are two statements:
Statement I: Transfer RNAs and ribosomal RNA do not interact with mRNA.
Statement II: RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence.
In the light of the above statements, choose the most appropriate answer from the options given below: