Final answer:
Dehydration synthesis is the preferred process because it can be used to create larger molecules, such as carbohydrates, from smaller components found in the environment, providing a source of energy for survival.
Step-by-step explanation:
Dehydration synthesis is the preferred process to utilize in this scenario. Dehydration synthesis is a reaction that combines two smaller molecules to form a larger molecule, releasing a molecule of water as a byproduct. In the context of being stranded on a desert island without food and water, dehydration synthesis could potentially be used to create larger molecules, such as carbohydrates, from smaller components found in the environment. This could help to provide a source of energy for survival.