The correct answer is: C. Lead
Lead is a heavy metal that is toxic to humans and other animals. It can be found in the air, water, soil, and food. Lead pollution can cause a variety of health problems, including brain damage, learning disabilities, and reproductive problems.
Copper is a metal that is essential for human health. It is found in small amounts in the body and helps to maintain the health of the nervous system, bones, and blood. Copper pollution can cause a variety of health problems, including anemia, kidney damage, and liver damage.
Chromium is a metal that is used in a variety of products, including stainless steel, paints, and pigments. Chromium pollution can cause a variety of health problems, including lung cancer, skin cancer, and kidney damage.
Cadmium is a metal that is used in a variety of products, including batteries, pigments, and stabilizers. Cadmium pollution can cause a variety of health problems, including kidney damage, bone disease, and cancer.
Lead is the most common metal that pollutes the air of a big city. It is released into the air from a variety of sources, including gasoline combustion, industrial emissions, and lead-based paint. Lead can be inhaled or ingested, and it can accumulate in the body over time. Lead poisoning can cause a variety of health problems, including brain damage, learning disabilities, and reproductive problems.