निम्नलिखित में से उस समूह का चयन कीजिए जिसमें केवल मिश्र धातुएँ (alloys) शामिल हैं:

Prolonged occupational exposure to excessive noise from heavy machinery without hearing protection causes noise-induced hearing loss. Excess noise is categorized as a:

Long-term exposure to indoor air pollutants, such as smoke from burning biomass fuels, significantly increases the risk of developing chronic respiratory conditions like: