Explanation

• The freezing point of water is 0°C (zero degrees Centigrade). 
• The boiling point of water on the Centigrade scale (also known as the Celsius scale) 100°C (one hundred degrees Centigrade).

Explanation

The usual gases used for lifting airships are hydrogen and helium.

Hydrogen is the lightest known gas and thus has great lifting capacity,

Helium is not as buoyant but is far safer than hydrogen because it does not burn.

Explanation

Venus is the brightest planet in the Solar System.

Explanation

علم الحشرات، وہ علم جو حشرات کی ساخت سے تعلق رکھتی ہے

Entomology Insects: کیڑے مکوڑے یا حشرات 

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Entomology is the study of insects and their relationship to humans, the environment, and other organisms.

RK12-12-22

Explanation

Water has maximum density at 4°C.

When Water is in its Solid form (Ice) below 0°C.

Explanation

The intensity of earthquake is measured by Richter Scale.

Richter Scale was invented in 1935.

Explanation

Cooking gas, also known as liquified petroleum gas (LPG), is a mixture of propane and butane.

It is a flammable mixture of hydrocarbon gases.

Explanation

• Sunlight is a good source of vitamin D.
• When our skin is exposed to sunlight, it produces vitamin D.
• It is essential for bone health, immune function, and the regulation of calcium levels in the blood.

Explanation

One of the early signs of vitamin A deficiency is night blindness (nyctalopia).

while

Vitamin K deficiency leads to uncontrolled bleeding during an injury.

A deficiency of Vitamin D results in Rickets

Explanation

Because sound is just vibrating air, space has no air to vibrate and therefore no sound in a vacuum.

Sound waves below 20 Hz are known as infrasound.

Sound waves above 20 kHz are known as ultrasound

Sound waves transmit a medium such as a gas, liquid, or solid.

• The speed of sound in air is about 343 meters per second
• The sound travels at 1,481 m/s in water 
• The speed of sound in a vacuum is zero meters per second.