Resources are materials or substances that have value and can be used to meet human needs and wants. They're classified into two main categories: renewable resources, which can be replenished naturally over time, and non-renewable resources, which are finite and cannot be easily replaced once depleted. Renewable resources include solar energy, wind power, and hydropower, while non-renewable resources include fossil fuels and minerals. The availability and distribution of resources vary across different regions of the world, playing a crucial role in economic development and quality of life.