Brass is an alloy of: MCQ with Answer and Explanation

Explanation:
The stratospheric ozone layer absorbs the majority of the sun's harmful ultraviolet (UV-B and UV-C) radiation, preventing it from reaching Earth's surface. UV can cause skin cancer, cataracts, and damage to ecosystems. Ozone depletion is caused by CFCs (chlorofluorocarbons). Infrared is associated with heat, visible light is mostly harmless, radio waves are not absorbed by ozone.

Explanation:
Biofuels like ethanol (from sugarcane), biodiesel (from plant oils), and biogas (from organic waste) are renewable as they can be replenished within a human lifespan. Coal, petroleum, and natural gas are fossil fuels, formed over millions of years, and are non-renewable. Using renewable fuels helps reduce greenhouse gas emissions. Another renewable fuel is hydrogen produced from water electrolysis using solar power.

Explanation:
Sodium lauryl sulfate (CH₃(CH₂)₁₁OSO₃Na) is a synthetic detergent with a sulfate group. Sodium stearate and potassium palmitate are soaps (carboxylate salts). Calcium oleate is soap scum.