Explanation

• The largest bone in the human body is the femur (the thighbone)
• It is located in the upper leg, between the hip and the knee.
• It supports the weight of the body and helps you walk, run, and stand
• It is about 48 centimeters (18 inches) long.

Additional information:

• The lowest part of the backbone is called the sacrum.
• The smallest bone is the stirrup (stapes).
• The strongest bone for its size is the lower jaw or mandible.

Last updated by NA on 09-09-2026

Explanation

• DNA stands for Deoxyribonucleic Acid.
• DNA is a biological molecule found in all living cells.
• It carries genetic information from parents to offspring.
• It controls growth, development, and body functions.
• DNA is present in the nucleus of cells (mainly in chromosomes).
• It is made of nucleotides arranged in a double helix structure.
• It was discovered by James Watson and Francis Crick (1953 structure model).

Last verified on 01-06-2026

Explanation

• The skin is considered the largest organ of the human body.
• It covering an area of about 1.5-2 square meters (16-22 square feet).
• It weighing around 3-4 kilograms (7-9 pounds).

Last verified on 01-09-2026

Explanation

• Humidity is the measure of the amount of moisture (water vapour) in the air.
• A hygrometer is used to measure relative humidity.
• A psychrometer is an example of a hygrometer.
• Relative humidity tells us the ratio of water vapour present in the air compared with the maximum amount the air can hold at a given temperature.
• Humidity is commonly expressed as a percentage (%).

Last verified on 23-08-2026

Explanation

• The law of universal gravitation was proposed by Isaac Newton.
• He introduced it in 1687 in his famous book Principia.
• It explains that every object attracts every other object.
• The force depends on mass and distance.

Last verified on 27-04-2026

Explanation

• Ozone (O₃) is mainly found in the Stratosphere, called the ozone layer.
• It absorbs harmful ultraviolet (UV) radiation from the sun, protecting life on Earth.
• Located roughly 15–35 km above the Earth’s surface.

Last verified on 17-01-2026

Explanation

• Urine is produced in the kidneys by filtering the blood.
• The kidneys remove excess water, salts, and waste products from the blood.
• Urine is formed in tiny filtering units called nephrons.
• After formation, urine passes through the ureters to the urinary bladder.
• The kidneys help maintain the body's fluid and electrolyte balance.

Last verified on 04-08-2026

Explanation

• Sunlight travels at the speed of light (~3 × 10⁸ m/s).
• Takes 8 minutes 20 seconds on average to reach Earth.
• Sunlight takes approximately 499 seconds to travel from the Sun to Earth.
• Distance traveled: 150 million km from Sun to Earth.
• Moonlight takes only 1.3 seconds to reach Earth.

Last verified on 13-03-2026

Explanation

• Nitrogen (N₂): 78%

Additional information:

• Oxygen (O₂): 21%
• Argon (Ar): 0.93%
• Carbon dioxide (CO₂): ~0.04%
• Other gases: ~0.03%

Last verified on 16-05-2026

Explanation

• A Fathometer is used to measure the depth of the ocean, sea, or any body of water.
• It determines the distance from the water surface to the seabed.
• The instrument works using sound waves (echo sounding).
• It measures the time taken for sound waves to travel to the seabed and return.

Additional information:

• Galvanometer → Measures electric current
• Barometer → Measures atmospheric pressure
• Thermometer → Measures temperature
• Hygrometer → Measures humidity

Last verified on 06-07-2026