Option 1 is incorrect. While it is true that camels have adaptations that allow them to conserve water, they still need water to survive.

Option 2 is also incorrect. While camels can metabolize stored fat to produce water, this is not the main reason why they can survive for long periods without drinking water.

Option 3 is partially correct. Camels do have a specialized organ called the water sac, which is located in the walls of the lumen of their stomach. This sac can store water and allow camels to go for extended periods without drinking. However, this is not the sole reason why camels can survive without water.

Option 4 is the correct answer. Camels can live without water for many days because they have a combination of adaptations, including their ability to conserve water, metabolize stored fat for water production, and the presence of the water sac in their stomach.