Why do many islands in the south pacific lack an adequate standard of living? the islands do not have any natural resources. the islands are too small to provide sufficient natural resources. constant warfare has weakened the economies of the islands. the climate is too harsh on the islands to properly support human life.

The answer is: The islands are too small to provide sufficient natural resources.

Because the island is small, you can assume that natural resources are limited. In fact, despite being surrounded by water, one of the major problems of these islands is they have little fresh water supply. Most of their fresh water is brought to them through precipitation. Freshwater is essential for humans and there are periods where they cannot obtain it.  

Ascenario that doesnt  include any modern objects like electricity

This type of energy is called radiant energy.