Explanation: Vitamin B₂ is also known as Riboflavin. It is a water-soluble vitamin that plays a vital role in the body’s energy production and cellular function. Riboflavin acts as a coenzyme in the metabolism of carbohydrates, fats, and proteins, helping to convert food into energy. It is also essential for maintaining healthy skin, eyes, and nerve functions. A deficiency of Vitamin B₂ can lead to cracked lips, sore throat, and inflammation of the tongue (a condition known as ariboflavinosis).

Explanation: Windows XP is an operating system (OS) developed by Microsoft. An operating system is system software that manages computer hardware, software resources, and provides services for running application programs. Windows XP, released in 2001, was one of the most popular OS versions used for both personal and business computers. It provides a graphical user interface (GUI), multitasking, and file management capabilities.

Explanation: Saliva, secreted by the salivary glands, begins the process of carbohydrate digestion in the mouth. It contains the enzyme salivary amylase (also known as ptyalin), which catalyzes the breakdown of starch (polysaccharide) into maltose (disaccharide). This is the first step in digestion, and it occurs while food is chewed and mixed with saliva before being swallowed.

Chemical Reaction:

Starch → (Salivary amylase) → Maltose

Thus, saliva plays an essential role in the digestion of carbohydrates, making the food slightly sweet when chewed for a longer time.

Explanation: A monitor is an output device that displays text, images, and videos generated by the computer. It allows users to visually view the processed data. Common types of monitors include LCD, LED, and OLED screens.

Explanation: EDUSAT (Education Satellite) was launched by the Indian Space Research Organisation (ISRO) in September 2004. It was the first Indian satellite built exclusively for educational purposes, designed to provide distance learning and interactive education through satellite communication.

Explanation: The full form of USB is Universal Serial Bus. It is a standard interface used to connect devices such as keyboards, mice, flash drives, and printers to a computer. USB allows data transfer and power supply between connected devices.

Explanation: Although most non-metals do not conduct electricity, graphite is an exception. In graphite, each carbon atom is bonded to three others, leaving one free electron that moves freely between layers, allowing it to conduct electricity efficiently.

Explanation: The blue colour of the sky is due to the scattering of sunlight by molecules and small particles in the Earth's atmosphere. Shorter wavelengths of light (blue and violet) are scattered more than longer wavelengths (red and yellow). Since our eyes are more sensitive to blue light, the sky appears blue.

Explanation: Vitamin K plays a crucial role in the blood clotting process. It helps the liver synthesize prothrombin and other clotting factors required to stop bleeding when injuries occur. Deficiency of Vitamin K can lead to excessive bleeding and delayed clot formation. Green leafy vegetables, broccoli, spinach, and intestinal bacteria are major natural sources of this vitamin.