| 1. | Snake and Frog | 2. | Chameleon and Turtle |
| 3. | Frog and Pigeon | 4. | Crocodile and Tiger |
| 1. | They lack the ability to internally regulate their body temperature. |
| 2. | Their four-chambered heart is not efficient in thermoregulation. |
| 3. | They are warm-blooded, but their temperature regulation is different from mammals. |
| 4. | The four-chambered heart is only related to oxygenation of blood, not temperature regulation. |