Explanation: Liquid Natural Gas (LNG) predominantly contains methane (CH₄) in liquid form. It is produced by cooling natural gas to about −162°C, which reduces its volume for easier storage and transportation. LNG is a clean fuel with high energy efficiency and low emissions.

Explanation: 1 Gigabyte (GB) is equal to 1024 Megabytes (MB). Computer memory and storage are measured in powers of 2 (binary system), where 1 KB = 1024 bytes, 1 MB = 1024 KB, and 1 GB = 1024 MB.

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.”

Xylem is a type of vascular tissue in plants responsible for the transportation of water and dissolved minerals from the roots to the stems and leaves. The upward movement of water through xylem vessels occurs due to processes like transpiration pull, root pressure, and capillary action. Xylem also provides mechanical support to the plant.

Other options (for context)

• Food: Transported by phloem, not xylem.
• Nutrient: Minerals are carried along with water but the primary function of xylem is water transport.
• Both food and water: Incorrect — only phloem transports food; xylem transports water.

Explanation: Shadows are formed when an opaque object comes in the path of light. Opaque objects do not allow light to pass through them, causing a dark region called a shadow to form on the opposite side. Transparent and translucent objects allow light to pass fully or partially, so they form faint or no shadows.

Explanation: Sound travels fastest in steel because it is a solid material where the particles are packed very closely together. Sound waves need a medium to travel, and their speed depends on how quickly vibrations can pass from one particle to another. In solids, particles are tightly bound, so vibrations are transmitted more efficiently. In contrast, sound travels slower in liquids and slowest in gases. It cannot travel through a vacuum because there are no particles to carry the vibrations.

Coal is a fossil fuel formed from the remains of plants that lived and died millions of years ago. Over long geological periods, heat and pressure converted these plant remains buried under soil and rock into coal. It is a major source of energy used for electricity generation, steel production, and various industrial processes. However, burning coal releases carbon dioxide, contributing to air pollution and global warming.

Other options (for context)

• Solar energy: A renewable energy source derived from sunlight, not a fossil fuel.
• Quartz: A mineral composed of silicon and oxygen, not an energy source.
• Lava: Molten rock from volcanic eruptions, not a fossil fuel.

Explanation: A concave mirror can produce an image that is larger than the object when the object is placed between the mirror’s pole and its focal point. This property makes concave mirrors useful in applications like shaving mirrors and makeup mirrors, where magnified images are needed.