Journey to the End of the Earth is a title given by the author to describe her journey because it symbolizes the vastness and remoteness of the destination. Let's explore the reasons why the author chose this title:

Crossing Multiple Time Zones:
- One of the reasons the author called her journey as Journey to the End of the Earth is because it involves crossing nine time zones. Time zones represent different regions of the world, and crossing multiple time zones indicates a long and challenging journey. The author's journey takes her far away from her starting point, reinforcing the idea of traveling to the very edge of the world.

Passing Through Checkpoints:
- The author mentions that her journey involves passing through six checkpoints. These checkpoints likely symbolize the various obstacles and challenges she faces along the way. By referring to her journey as Journey to the End of the Earth, the author highlights the arduous nature of her expedition and the determination required to overcome these hurdles.

Navigating Water Bodies:
- Another aspect of the author's journey is crossing three water bodies. Water bodies, such as rivers, seas, or oceans, can be significant barriers and require careful planning and navigation. By including this detail, the author emphasizes the physical difficulties involved in reaching her destination, further justifying the title Journey to the End of the Earth.

Exploring Different Ecospheres:
- The author also mentions encountering different ecospheres during her journey. Ecospheres refer to distinct ecological systems or environments. By exploring various ecospheres, the author highlights the diversity and richness of the natural world. Additionally, encountering different ecospheres reinforces the idea of venturing to the farthest reaches of the Earth, where unique and unexplored environments exist.

Conclusion:
In conclusion, the author called her journey as Journey to the End of the Earth because it involves crossing multiple time zones, passing through checkpoints, navigating water bodies, and exploring different ecospheres. Each of these elements contributes to the idea of a challenging and remote expedition, symbolizing the vastness and remoteness of the destination.