Study the following and pick up the correct combinations
| S.No. | Group | Salient Feature | Example |
|---|---|---|---|
| I | Aves | Pneumatic bones | Columba |
| II | Mammalia | Corpus callosum | Macaca |
| III | Reptilia | Epidermal scales | Calotes |
| IV | Chondrichthyes | Cartilagenous skeleton | Scoliodon |
Find the variance of the following frequency distribution:
| Class Interval | ||||
| 0--4 | 4--8 | 8--12 | 12--16 | |
| Frequency | 1 | 2 | 2 | 1 |