Guinness World Records (General Knowledge Focus) MCQs with Answers & Explanations (Page 486)

Explanation Collagen is a structural protein that f orms strong fibers in bones. It provides tensile strength and flexibility, preventing bones from breaking easily. Collagen works together with calcium phosphate to maintain bone rigidity. Loss of collagen with age can lead to brittle bones and osteoporosis.

Explanation I nfiltration is the process by which w ater enters the soil from the surface. It helps replenish groundwater and maintain soil moisture. Additional information Percolation is the downward movement of water through soil layers. Evaporation is the conversion of water into vapor, and transpiration is water loss from plants.

Explanation An ecosystem develops through a series of successional stages. The final, stable stage is called the climax community. It is characterized by a balanced and self-sustaining ecosystem.

Explanation Luminosity is the total amount of energy a star emits per second. It depends on the star's size and temperature. Brightness is how bright the star appears from Earth, which can vary with distance. Magnitude is a scale t o measure stellar brightness.

Explanation P waves (primary waves) are the fastest seismic waves generated during an earthquake. They travel through solids, liquids, and gases, compressing and expanding the material. S waves (secondary waves) are slower and c an only move through solids. P waves are the first to be detected by seismographs. Their higher speed helps in early warning systems for earthquakes.

Explanation Glucose is mainly synthesized in plant s through photosynthesis. Carbon dioxide provides the carbon atoms needed for glucose formation. Water (H₂O) provides hydrogen and electrons but does not contribute carbon.

Explanation The main purpose of cellular respiration is to convert chemical energy stored in nutrients (specifically glucose) into ATP (adenosine triphosphate), They acts as the usable energy currency for cellular processes. It breaks down glucose in the presence of oxygen to produce ATP, carbon dioxide, and water.

Explanation A toxin is a poison produced naturally by a plant . It protects the plant from herbivores and pathogens . Additional information : Examples of toxic plants: Ricinus (Castor), Nerium (Oleander), Datura, Aconitum, Foxglove Last verified on 25-01-2026

Explanation Cellular activities require energy to function, which comes from molecules like ATP . ATP (adenosine triphosphate) stor es energy in its phosphate bonds. When a phosphate bond is broken, energy i s released for cellular processes. This energy powers activities like muscle contrac tion, nerve signaling, and biosynthesis. Therefore , phosphate bonds ar e the primary s ource of energy in metabolism.

Explanation Diabetes mellitus is a metabolic disorder where the body cannot properly regulate blood glucose. It occurs due to insufficient insulin production or poor insulin response. High blood sugar over time can damage organs like th e heart, kidneys, and eyes. Symptoms include frequent urination, excessive thirst, and unexplained weight loss.

Explanation Noble gas atoms generally do not form bonds under normal conditions Due to their full valence electron shells , making them highly stable and inert. However, under extreme pressure, low temperatures, or with highly reactive elements like fluorine and oxygen, They can form compound bonds, primaril y involving heavier gases like xenon.

Explanation Fossil fuels like coal, oil, and natural gas are primarily composed of carbon and h ydrogen. These elements are stored energy from ancient plants and organisms. When burned, they release energy along wit h carbon dioxide and water. The high carbon and hydrogen content makes them excellent sources of fuel. Oxygen and nitrogen are present in very small amounts compared to carbon and hydrogen.

Explanation LPG (Liquefied Petroleum Gas) Mainly consists of hydrocarbons like propane and butane . These are gases composed of hydrogen and carbon atoms. It is used as fuel for cooking and heating .

Explanation Air always moves from regions of high pressure to low pre ssure. This movement creates win d and drives weather patterns. The greater the pressure difference, the stronger the wind. High-pressure areas are usually associated with clear skies. Low-pressure areas often brin g clouds and precipitation.

Explanation A comet moves fastest when it is closest to the Sun, called perihelion. The Sun's gravity pulls the com et strongly, increasing its speed. At aphelion (farthest point from the Sun), its speed is much slower. This follows Kepler's laws of planetary motion. The increase in speed also causes the comet' s tail to become more visi ble.

Explanation The Sun produces energy through nuclear fusion in its core. In fusion, hydrogen nuclei combine to form helium, releasing huge energy. This energy radiates as sunligh t, heat, and solar radiation. Fusion is different from fission, which splits heavy nuclei. Solar energy powers life on Earth and can be harnessed for electricity.

Explanation Submandible refers to the area under the lower jaw (mandible). It is close to th e ear region. It contains submandibular glands, which are salivary glands.

Explanation Nitrobacter bacteria convert nitrite (NO₂⁻) into nitrate (NO₃⁻) in the soil. This is the second step of the nitrification process , which is important for plant nutrition. Nitrite is toxic to plants, but nitrate is easily absorbed as a nutrient. Last verified on 22-01-2026

Explanation Perihelion is the point in a comet 's orbit closest to the Sun. According to Kepler's Second Law, a comet moves faster when closer to the Sun. Aphelion is the farthest point from th e Sun, where speed is minimum. The increase in speed is due to Sun's gravitational pull. This principle applies to all celestial bodies in elliptical orbits.

Explanation A cell is the basic structural and functional unit of life. All plant and animal tissues are made up of cells. Nitrogen, phosphorus, and oxygen are elements , not units of tissue.