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 |
The current passing through the battery in the given circuit, is:
Three identical heat conducting rods are connected in series as shown in the figure. The rods on the sides have thermal conductivity 2K while that in the middle has thermal conductivity K. The left end of the combination is maintained at temperature 3T and the right end at T. The rods are thermally insulated from outside. In steady state, temperature at the left junction is \(T_1\) and that at the right junction is \(T_2\). The ratio \(T_1 / T_2\) is