Flying squirrel & flying phalanger represent the phenomenon of :

Answer

**Step-by-Step Solution:**

1. **Understanding the Organisms**: The question refers to the flying squirrel and the flying phalanger. The flying squirrel is a placental mammal found in various parts of the world, while the flying phalanger (or sugar glider) is a marsupial native to Australia and New Guinea.

2. **Identifying the Evolutionary Phenomenon**: We need to determine which evolutionary phenomenon these two organisms represent. The options given are divergent evolution, convergent evolution, and adaptive radiation.

3. **Divergent Evolution**: This type of evolution occurs when two or more related species become more dissimilar over time, often due to different environmental pressures. This is typically represented by homologous structures, which are similar in structure due to common ancestry.

4. **Convergent Evolution**: This occurs when unrelated species develop similar traits or adaptations due to similar environmental pressures, despite not sharing a common ancestor. This is represented by analogous structures, which perform similar functions but have different anatomical structures.

5. **Adaptive Radiation**: This is a process where organisms diversify rapidly into a wide variety of forms to adapt to different environments. It often occurs when a species colonizes a new area with diverse habitats.

6. **Analysis of Flying Squirrel and Flying Phalanger**: Both the flying squirrel and flying phalanger have developed similar adaptations for gliding, despite belonging to different groups (placental mammals and marsupials, respectively). This similarity in function, despite their different evolutionary backgrounds, indicates convergent evolution.

7. **Conclusion**: Therefore, the flying squirrel and flying phalanger represent the phenomenon of **convergent evolution**.

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