Natural resource
When people do not have some resources, their quality of life can get lower.  So, people protect resources.  When they can not get clean water, people may become ill; if there is not enough wood, trees will be cut and the forest will disappear over time (deforestation); if there are not enough fish in a sea, people can die of starvation.  Renewable resources include crops, wind, hydroelectric power, fish, and sunlight.  Many people carefully save their natural resources so that others can use them in future.