Which of the following is an organic fertilizer? MCQ with Answer and Explanation

Explanation:
Cinnabar is HgS, the chief ore of mercury. Bauxite (Al), galena (Pb), magnetite (Fe). Mercury is extracted by roasting cinnabar in air: HgS + O₂ → Hg + SO₂.

Explanation:
The ozone layer is located in the lower stratosphere (~15-35 km altitude), where ozone concentration is highest. It absorbs harmful ultraviolet radiation (UV-B and UV-C) from the sun. Ground-level ozone (troposphere) is a pollutant and component of smog, harmful to health. Ozone depletion is caused by chlorofluorocarbons (CFCs) which release chlorine atoms that catalytically destroy O₃.

Explanation:
Arsenic (As) is a metalloid, showing properties of both metals and non-metals. It is in group 15, period 4. Sodium and calcium are metals. Oxygen is a non-metal. Metalloids: B, Si, Ge, As, Sb, Te. They are semiconductors and form amphoteric oxides.