ResourcesResources are found in nature. They make a better quality of life for humans. Soil, air, water, sunlight and trees are all examples of resources that humans use every day, whether they know it or not._____（26） A natural resource is a material fund in nature and used by living things. Air, rocks, metals, oil and salt are all natural resources. Renewable（可再生的）resources are resources that can be replaced._____（27）Trees that are cut down can be replaced quickly when seeds or baby trees are planted. Water from our bathtubs（浴盆）can be cleaned for use. Plants, wind and rain can help clean the air to make it safe to breathe even if it comes out of a car or a factory.Sometimes resources cannot be replaced after they are used._____（28）Once nonrenewable resources are all used up, nature will not be able to replace them. Oil, natural gas, soil and metals are all examples of nonrenewable resources.Coal is another example of a nonrenewable resource._____（29）Humans mine the coal underground and use it as an energy source. Once humans have mined all the coal from inside Earth, there will be on more for us to depend on._____（30）For example, wind and water turbines（涡轮机）are now being used to produce energy._____.