Explanation: The sex of a newborn baby is determined by the chromosome inherited from the father. Humans have 23 pairs of chromosomes — 22 pairs of autosomes and one pair of sex chromosomes. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The mother always contributes an X chromosome, but the father can contribute either an X or a Y. If the sperm carrying an X chromosome fertilizes the ovum, the child will be a girl (XX); if the sperm carries a Y chromosome, the child will be a boy (XY).

Explanation: Rakesh Sharma was the first Indian astronaut to travel into space. He flew aboard the Soviet spacecraft Soyuz T-11 on April 3, 1984, as part of a joint mission between ISRO (Indian Space Research Organisation) and the Soviet Intercosmos program. During his space mission, he spent about 8 days aboard the Salyut-7 space station. When asked by then Prime Minister Indira Gandhi how India looked from space, he famously replied, “Saare Jahan Se Achha.”

Explanation: Alcohols are organic compounds composed of carbon (C), hydrogen (H), and oxygen (O). They are characterized by the presence of one or more hydroxyl (-OH) functional groups attached to a carbon atom. The general formula of alcohols is C_nH_2n+1OH. A common example is ethanol (C₂H₅OH), which is used in beverages, fuels, and sanitizers. The -OH group makes alcohols polar, soluble in water (especially lower alcohols), and reactive in many organic reactions.

Explanation: Sound waves in air are longitudinal waves, meaning the particles of the medium vibrate back and forth in the same direction as the wave travels. These waves require a material medium (like air, water, or solids) for propagation and cannot travel through a vacuum.

Explanation: The quality of petrol (gasoline) is measured by its octane number, which indicates the fuel's resistance to knocking (premature ignition) in an internal combustion engine; a higher octane number gives better performance and smoother operation.

Explanation: Every computer connected to the Internet is identified by a unique numerical label called an IP Address (Internet Protocol Address). It consists of four numeric parts separated by dots (e.g., 192.168.1.1) and is used to locate and communicate with devices over the network.

Explanation: Aerosols (such as those used in spray cans, refrigerants, and air conditioners) often contain chlorofluorocarbons (CFCs) and other halogen compounds. These chemicals rise to the stratosphere, where ultraviolet (UV) radiation breaks them down, releasing chlorine atoms. Each chlorine atom can destroy thousands of ozone (O₃) molecules, leading to ozone layer depletion. The thinning of the ozone layer allows more harmful UV rays to reach Earth, increasing the risk of skin cancer, eye damage, and affecting ecosystems.

Explanation: Haemoglobin is a complex iron-containing protein found in red blood cells (RBCs). It binds with oxygen in the lungs to form oxyhaemoglobin and releases it in tissues where oxygen levels are low. It also helps transport carbon dioxide from tissues back to the lungs. This oxygen-carrying property makes haemoglobin the essential respiratory pigment in humans and most vertebrates.

Explanation: CNG stands for Compressed Natural Gas. It is an eco-friendly fuel made primarily of methane (CH₄) and is used as an alternative to petrol and diesel. CNG burns cleanly, producing fewer pollutants and helping reduce air pollution.