Everyday Science

Onion seeds are typically rectangular in shape, unlike the other options whose seeds are round or differently shaped. Therefore, the vegetable crop with rectangular seeds is Onion.

Atmospheric pressure decreases rapidly with altitude because the air becomes less dense as altitude increases, resulting in fewer air molecules exerting pressure.

Oil rises in the wick of an oil lamp due to capillary action, which is the ability of a liquid to flow in narrow spaces without external forces, caused by adhesion and cohesion.

Specific gravity is a ratio of the density of a substance to the density of a reference substance (usually water), making it a dimensionless quantity with no units.

Oxygen is essential for burning because it supports the chemical reaction of combustion. Without oxygen, burning cannot occur.

Lemons are sour because they contain citric acid, which gives them their characteristic tart taste. The other acids listed are found in different substances and do not primarily cause the sourness in lemons.

In soap manufacture, oils (fats) react with sodium hydroxide to produce soap and glycerine as a by-product. Therefore, glycerine is obtained during the process.

Hydrogen is the most abundant element in the human body by number of atoms, primarily because water (H2O) makes up a large portion of the body and contains hydrogen atoms. Oxygen is abundant by mass but not by atom count. Blood and protein are not elements.

Retinol is the chemical name for Vitamin A, which is essential for vision, growth, and immune function. The other options correspond to different vitamins with distinct chemical names.

The thickness of the ozone layer is measured in Dobson Units, which quantify the total amount of ozone in a column of the atmosphere.

The second largest component in milk after water is protein. Fat is the third largest component. Vitamins are present in very small amounts, and 'None of these' is incorrect.

A hypsometer is an instrument used to measure height or altitude above sea level by determining the boiling point of water, which changes with atmospheric pressure. The other options measure different parameters: a hygrometer measures humidity, a pyrometer measures high temperatures, and a solometer is not a standard instrument.

The standard unit for measuring home electricity consumption is the kilowatt-hour (kWh), which represents the energy used when one kilowatt of power is consumed for one hour. This unit is commonly used by electricity meters and billing systems.

Vitamin B-6 is known as Pyridoxine. It plays an important role in metabolism and brain function, distinguishing it from other B vitamins such as B-1 (Thiamine), B-2 (Riboflavin), and B-12 (Cobalamin).

A washing machine works on the principle of centrifugation, where rapid spinning removes water from clothes by using centrifugal force.

Red-green color blindness includes both protanopia (difficulty distinguishing red) and deuteranopia (difficulty distinguishing green). Since both are types of red-green color blindness, the correct answer is 'both a & b'.

Vitamin B-7 is known as Biotin. It plays an important role in metabolism and is essential for healthy skin, hair, and nails.

H5N1 is a subtype of the influenza virus that causes bird flu, also known as avian influenza. It is not related to AIDS or general fever, and 'non' is not a valid answer.

The Nobel Prize is widely recognized as the most prestigious award in the field of science, honoring outstanding contributions in physics, chemistry, medicine, and related disciplines. The other options are either unrelated to science or less prominent in this context.

The spleen is called the 'Blood Bank' because it stores a reserve of blood and helps filter and manage blood cells in the body. None of the other organs listed serve this function.

Transport is often called the 'Lifeblood of industries' because it enables the movement of raw materials to factories and finished goods to markets, which is essential for industrial operations.

Heat exchanger tubes are typically made from metals like carbon steel, stainless steel, or copper due to their good thermal conductivity and mechanical properties. Lead is not used because it is soft, has poor mechanical strength, and is toxic, making it unsuitable for heat exchanger tubes.

A nephoscope is an instrument specifically designed to determine the direction of movement of clouds, making option A correct. Stethoscope is used for listening to internal body sounds, and metroscope is not a standard meteorological instrument.

Nickel (Ni) is commonly used as a catalyst in the hydrogenation of oils because it facilitates the addition of hydrogen to unsaturated fats, converting them into saturated fats. Lead (Pb), copper (Cu), and platinum (Pt) are not typically used for this process.

Archaeology is a branch of Anthropology that studies human history and prehistory through the excavation of sites and analysis of artifacts and other physical remains. Therefore, option A is correct.