The correct answer is A. Lead.
Lead is a heavy metal that is toxic to humans. It can be found in the air, water, and soil, and it can be absorbed into the body through the lungs, skin, and digestive system. Lead poisoning can cause a variety of health problems, including mental disorders, such as attention deficit hyperactivity disorder (ADHD), learning disabilities, and memory problems.
Lead is a major pollutant from motor car exhaust. When gasoline is burned, lead is released into the air. This lead can then be inhaled by people, or it can be deposited on surfaces and then ingested by people who touch those surfaces.
Lead poisoning is a serious problem, and it is important to take steps to reduce exposure to lead. These steps include:
- Avoiding areas with high levels of lead in the air, water, or soil.
- Having children’s blood lead levels tested regularly.
- Removing lead-based paint from homes and businesses.
- Using lead-free gasoline.
If you are concerned about lead exposure, you should talk to your doctor.
The other options are incorrect because they are not pollutants from motor car exhaust.
- Option B, NO2, is nitrogen dioxide. Nitrogen dioxide is a gas that is produced when fossil fuels are burned. It can cause respiratory problems, such as asthma and bronchitis.
- Option C, SO2, is sulfur dioxide. Sulfur dioxide is a gas that is produced when fossil fuels are burned. It can cause respiratory problems, such as asthma and bronchitis.
- Option D, Hg, is mercury. Mercury is a metal that is found in some types of batteries. It can be released into the environment when batteries are disposed of improperly. Mercury can cause a variety of health problems, including neurological problems, such as tremors and memory loss.