Statement 2 is correct. Nanoparticles of certain metallic oxides, such as titanium dioxide (TiO₂) and zinc oxide (ZnO), are commonly utilized in the manufacture of cosmetics, particularly sunscreens. Their small size enhances UV-blocking properties while maintaining transparency on the skin.
Statement 3 is correct. There is significant scientific concern regarding the potential health and environmental risks posed by nanoparticles from commercial products once they enter the environment. Their minute size allows them to penetrate biological membranes, accumulate in various organs, and potentially exert toxic effects on humans and ecosystems. Research is ongoing to fully assess these risks.
Statement 1 is incorrect. Nanoparticles are not exclusively man-made; they occur widely in nature. Natural sources include volcanic ash, ocean spray, forest fires, and products of biological processes and geological weathering. Therefore, the assertion that nanoparticles do not exist in nature other than those made by humans is false.
Option (a) is incorrect because it states only Statement 1 is correct, whereas Statement 1 is false.
Option (b) is incorrect because while Statement 3 is correct, Statement 2 is also correct, making this option incomplete as it excludes a correct statement.
Option (c) is incorrect because it includes Statement 1, which is false.