Explanation

• Vitamin A deficiency → Night blindness (Nyctalopia)
• Vitamin A is important for vision and immune function.

Additional information:

• Vitamin K is essential for blood clotting.
• Vitamin D helps in calcium absorption and bone mineralization.
• Vitamin B1 supports nerve function and energy metabolism.

Last verified on 01-02-2026

Explanation

• Edward Jenner was an English physician and scientist.
• He discovered the first vaccine for smallpox in 1796.
• He observed that milkmaids infected with cowpox were protected from smallpox.
• This led to the development of vaccination (cowpox-based immunity method).
• He is known as the Father of Immunology.

Last verified on 02-05-2026

Explanation

• Hydrogen (H2) and Argon is not a greenhouse gas.
• Greenhouse gases are gases that trap heat in Earth’s atmosphere and cause the Greenhouse Effect.

The main greenhouse gases are:

• Carbon dioxide (CO2)
• Methane (CH4)
• Nitrous oxide (N2O)
• Water vapor (H2O)
• Ozone (O3)
• Chlorofluorocarbons (CFCs)
• Hydrofluorocarbons (HFCs)
• Perfluorocarbons (PFCs)

Last verified on 01-05-2026

Explanation

Composition of Air:

• Nitrogen → 78%
• Oxygen → 20.95%
• Argon → 0.93%
• Carbon dioxide → 0.04%
• Other gases → very small traces

Last verified on 30-04-2026

Explanation

• Vitamin A is essential for vision, skin health, and immune function.
• Its deficiency can lead to night blindness (poor ight vision) and other health problems.

Additional information:

• Dry skin and eyes
• Impaired immune function
• Poor wound healing
• Increased risk of respiratory and urinary tract infections

Last verified on 17-01-2026

Explanation

• Washing soda is also known as sodium carbonate (Na2CO3).
• It is used to remove permanent hardness of water.
• Permanent hardness is caused by the presence of magnesium and calcium sulfates or chlorides in water, which cannot be removed by boiling.
• Washing soda helps to precipitate these minerals, making the water softer.

Last verified on 23-04-2026

Explanation

• A barometer measures atmospheric (air) pressure.
• It helps in weather forecasting, detecting storms, and studying climate changes.
• Two common types of barometers: mercury barometer and aneroid barometer.

Last verified on 13-03-2026

Explanation

• Solids → fastest sound speed
• Liquids → medium speed
• Gases → slowest speed

Steel is more elastic and dense.

• Steel ≈ 5000 m/s
• Air ≈ 332 m/s
• Water ≈ 1500 m/s

Last verified on 11-04-2026

Explanation

• Chronometer is a highly precise time-measuring instrument.
• It is often used in navigation and scientific experiments.
• It is designed to measure time accurately, even under varying conditions.
• Chronometers played a key role in determining longitude at sea.

Last verified on 03-04-2026

Explanation

• Oncology is a branch of medicine that deals with the study, treatment, diagnosis, and prevention of cancer.
• A medical professional who practices oncology is an oncologist.
• The name's etymological origin is the Greek word ὄγκος, meaning "tumor", "volume" or "mass".

Last verified on 03-04-2026