Explanation

Chlorine is the gas used to disinfect and purify water.

It is passed through water to kill bacteria.

Explanation

• Red (R) Green (G) and blue (B) colors are known as primary colors of light.
• Because of mixing these three colors we are able to make all possible colors.

Key Point

The primary colors of Pigment is:

• Red
• Yellow
• Blue

Explanation

جب کوئی انسان جگر میں سوجن کا شکار ہوجائے تو اس بیماری کو ہیپاٹیٹس کہا جاتا ہے۔

One person in every 30 seconds die due to Hepatitis in the world.

Explanation

Horticulture is the agriculture of plants

Agrostology: Study of Grasses 

Agronomy: soil management and crop production 

Odontology: Study of teeth 

Arthrology: Study of joints 

Nephrology: Study of kidneys

Hematology: Study of blood  

Dermatology: Study of skin 

Explanation

The poles experience six months of the day and six months of the night.

This is since earth is tilted on its axis.

Also, due to this, each pole is tilted towards and away from the sun for about six months.

When the North Pole is tilted towards the sun, it has continuous daylight.

Explanation

Joseph Priestly discovered oxygen on August 1, 1774.

The most abundant element in the Earth's crust is oxygen.

It making up 46.6% of Earth's mass.

Explanation

Explanation

Gases and particles in Earth's atmosphere scatter sunlight in all directions.

Blue light is scattered more than other colors because it travels as shorter, smaller waves.

This is why we see a blue sky most of the time.

ND-21-5-2023

Explanation

Albert Einstein received his Nobel Prize one year later, in 1922.

Received the Noble Prize for his discovery of the Law of the photoelectric effect

He proposed that light behaves like a stream of particles called photons with an energy of E=hv

Explanation

AIDS stands for Acquired Immunodeficiency Syndrome.

It is caused by the HIV virus.

The virus primarily attacks the immune system.

This weakens the body's defense against infections and diseases.