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

• The chemical name of chalk is Calcium carbonate.
• Its chemical formula is CaCO₃.
• It is a soft, white mineral.
• Commonly used in blackboard chalk and limestone.
• Found naturally in rocks and marine shells.

Last verified on 30-04-2026

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

Explanation

• Eccrine sweat glands help regulate body temperature.
• They are most densely found on palms and soles.
• These glands produce watery sweat for cooling.
• They are active throughout the body, especially in these areas.
• This helps maintain body temperature balance.

Last verified on 26-04-2026

Explanation

• Evaporation is the process of liquid changing into vapor.
• During this process, heat is absorbed from the surroundings.
• This causes a drop in temperature (cooling effect).
• That is why sweating cools the human body.
• Evaporation is a natural cooling phenomenon.

Last verified on 26-04-2026

Explanation

• Venus is the brightest planet.
• It has an atmosphere but no moons.
• It's identical in size, chemistry and gravity.
• It has volcanoes, mountains and sand.
• It's also called Sister Planet of the Earth.

Last verified on 25-04-2026

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

• Sugar is the most soluble chemical in water.
• Sugar is made from sucrose.
• Sugar dissolves readily in water due to its polar nature.
• It forms hydrogen bonds with water molecules, increasing solubility.
• Used widely in food and beverages due to easy dissolution.

Last verified on 23-04-2026