Magnetite particles, suspected to cause neurodegenerative problems, are generated as environmental pollutants from which of the following? 1. Brakes of motor vehicles 2. Engines of motor vehicles 3. Microwave stoves within homes 4. Power plants 5. Telephone lines Select the correct answer using the code given below.

1. The question asks for the sources of magnetite particles as environmental pollutants, which are suspected to cause neurodegenerative problems. 2. Item 1: Brakes of motor vehicles - Friction during braking wears down brake pads and discs, releasing fine particulate matter, including iron oxides like magnetite. This is a known source. Correct. 3. Item 2: Engines of motor vehicles - Internal combustion engines release exhaust fumes containing various pollutants, including metallic particles derived from fuel, lubricants, and engine wear. Magnetite can be among these emissions. Correct. 4. Item 3: Microwave stoves within homes - Microwave stoves use electromagnetic radiation to heat food. They are not a significant source of airborne magnetite particle pollution. Incorrect. 5. Item 4: Power plants - Fossil fuel combustion, especially coal, in power plants releases fly ash containing various minerals, including iron oxides like magnetite. Correct. 6. Item 5: Telephone lines - Telephone lines transmit electrical signals and do not generate magnetite particles as environmental pollutants. Incorrect. Therefore, brakes and engines of motor vehicles, and power plants are sources.