Marsupials survived in Australia, but not in Asia. Because:

Options

A. Climate of Australia is cold
B. Marsupials lack competition in Australia from other mammals
C. Marsupials have high reproductive capacity
D. Australia has a rich diversity of vegetations

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: Marsupials are a group of mammals that include kangaroos, koalas, and opossums. They are primarily found in Australia and are known for their unique reproductive system, where young are carried in a pouch.

2. **Geological History**: In prehistoric times, Australia was connected to Asia. However, it eventually separated from the Asian continent. This separation played a crucial role in the evolution and survival of marsupials.

3. **Evolution of Mammals**: After the separation, eutherian mammals (placental mammals) evolved in Asia. These mammals were often carnivorous and competed for resources, which included food and habitat.

4. **Competition in Asia**: The presence of eutherian mammals in Asia created a competitive environment that was detrimental to the survival of marsupials and prototherians (egg-laying mammals). As a result, marsupials could not thrive in Asia due to this competition.

5. **Survival in Australia**: In contrast, when marsupials migrated to Australia, they encountered a different environment with fewer competing mammals. This lack of competition allowed marsupials to flourish and diversify in Australia.

6. **Conclusion**: Therefore, the primary reason marsupials survived in Australia but not in Asia is due to the lack of competition from other mammals. Other factors such as climate, reproductive capacity, and vegetation were not the main reasons for their survival.

**Final Answer**: Marsupials survived in Australia but not in Asia because they lacked competition from other mammals.

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