Following are the correct options for this question:
- Build more windmills
- Develop cost-efficient solar energy
- Improve gas mileage in cars
- Reduce the use of nonrenewable energy sources
Any undesirable change occurs in the air due to addition of pollutants is called air pollution. The major air pollutants are sulfur dioxide which is released from the combustion of fossil fuels like coal, petroleum and from factories. Bedsides, sulfur dioxide dust and smokes are other pollutants. Building of more wind mills and developing low cost solar energy will reduce air pollution as they will provide clean energy and will reduce dependency on coal burning in thermal power plant. Improving as mileage in cars will also reduce emission of sulfur dioxide, hence reduce air pollution. Building of more wind mills and developing low cost solar energy are renewable source of energy, will reduce use of nonrenewable energy sources such as fossil fuels.
C is the best answer for this
Development of more railroad systems contributed
most to US westward expansion in the second half of the nineteenth century.
The correct answer between all the choices given is the second choice or
letter B. I am hoping that this answer has satisfied your query and it will be
able to help you in your endeavor, and if you would like, feel free to ask
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