The correct answer is: d) All of the above.
Sand and gravel are essential materials for a wide range of construction projects, including roads, buildings, and dams. They are also used in the production of concrete, glass, and other materials. The global demand for sand and gravel is estimated to be over 40 billion tons per year, and this demand is expected to grow significantly in the coming years.
The overexploitation of sand and gravel resources can have a number of negative environmental impacts, including:
- Degradation of riverbeds and coastlines
- Loss of biodiversity
- Sedimentation of waterways
- Groundwater depletion
- Air pollution
In addition, the overexploitation of sand and gravel resources can also have a number of social and economic impacts, including:
- Conflicts over land use
- Loss of jobs in the construction sector
- Increased costs of construction materials
- Damage to infrastructure
It is important to manage sand and gravel resources sustainably in order to avoid these negative impacts. This can be done by:
- Reducing the demand for sand and gravel
- Recycling and reusing sand and gravel
- Using alternative materials
- Planning and managing sand and gravel extraction sites carefully
By taking these steps, we can help to ensure that sand and gravel resources are available for future generations.