Tag: science & technology

Red soil is typically high in iron oxide and aluminum, making it acidic, nutrient-poor, and difficult to cultivate compared to other soil types. Alluvial soil (deposited by rivers) is very fertile, black soil (regur) is excellent for cotton cultivation, and sandy soil, while less fertile, is easier to work with than hard, compacted red soil. Red soil requires significant amendments for agriculture.

Lead pollution from vehicle exhaust (leaded gasoline) and industrial emissions was a major air pollutant in busy cities before environmental regulations phased it out. While cadmium, chromium, and copper can be toxic pollutants, lead was historically the most significant metal pollutant in urban air due to its widespread use in fuel. Lead poisoning was a serious public health concern in cities.

Kaziranga National Park in Assam, India, is most famous for its population of the one-horned rhinoceros (Rhinoceros unicornis), which it has successfully conserved. While it does have tigers, they're not the primary attraction. Gir lions are found in Gir Forest National Park in Gujarat, and while Kaziranga has birds, it's not primarily known as a bird sanctuary (unlike Bharatpur).

Hydrogenation is the correct process for converting liquid cooking oils into solid vegetable ghee (vanaspati). During hydrogenation, hydrogen gas is bubbled through the oil in the presence of a nickel catalyst, adding hydrogen to the double bonds in unsaturated fatty acids, which increases the melting point and makes the oil solid at room temperature.

Bauxite is the correct answer because it is the principal ore of aluminum that exists in hydrated forms in nature. Bauxite contains aluminum hydroxide minerals like gibbsite (Al(OH)3), boehmite (AlO(OH)), and diaspore (AlO(OH)), which are all hydrated forms of aluminum oxide. Haematite (Fe2O3), carbonates, and sulphides are not typically found as hydrated ores.

A red giant is a star that has low surface temperature (appearing red) but has expanded to a diameter much larger than the sun due to stellar evolution. A supernova is a stellar explosion. A quasar is an extremely luminous active galactic nucleus. A nebula is a cloud of gas and dust in space.

Diamond is the hardest known natural mineral on the Mohs scale (rating 10) and is a pure allotrope of carbon, meaning it consists entirely of carbon atoms arranged in a crystal lattice structure. Zircon, quartz, and garnet are much softer minerals with different chemical compositions.

The mandible is the lower jawbone. Moving the mandible primarily occurs during chewing (mastication), speaking, and yawning. While dreaming and lifting weights don't require mandible movement, and playing piano uses hands/fingers, chewing food is the activity that directly involves the rhythmic opening and closing of the mandible to break down food.