Explanation

Dmitri Mendeleev, a Russian chemist, formulated the Periodic Table in 1869, arranging chemical elements according to their atomic number (number of protons in the nucleus) and chemical properties.

He organized the elements in a logical and systematic order.

This making it easier to predict their behavior and relationships.

Explanation

Chlorine is a strong oxidant that rapidly kills many harmful microorganisms.

Chlorine is a toxic gas.

Explanation

The discoverer of the cause of Malaria is Ronald Ross

Alphonse Laveran, a French army doctor, described the malarial parasite--

And proposed that it caused malaria in 1880.

Explanation

Flatworms (phylum Platyhelminthes) have unsegmented, flat bodies.

Earthworms and tapeworms have segmented bodies.

Explanation

Most abundant element in Earth crust is Oxygen.

Oxygen in the crust is (46.1%).

The chemical formula of oxygen (dioxygen) is O2.

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List of 10 Most Abundant Elements in the Earth's Crust

Explanation

Three Primary Colors : Red, Yellow, Blue.

Three Secondary Colors : Orange, Green, Violet.

Six Tertiary Colors : Red-Orange, Yellow-Orange, Yellow-Green, Blue-Green, Blue-Violet, Red-Violet,

which are formed by mixing a primary with a secondary.

Explanation

• Red Phosphorus is the primary substance used in matchsticks 

Additional information:

• Sulphur: Only acts as a secondary fuel in the match head to keep the flame burning.
• Zinc: Completely unused in the chemical composition of standard matches.

Last updated 18-07-2026 by NA

Explanation

Dialysis is a medical treatment used when the kidneys are unable to filter waste products from the blood, typically in renal (kidney) failure.

It helps maintain proper fluid and electrolyte balance in the body.

Explanation

• Sulfur dioxide (SO₂) and Nitrogen dioxide (NO₂) (nitrogen oxides, NOₓ) cause acid rain.
• These gases are mainly released from burning fossil fuels.
• SO₂ dissolves in rainwater to form sulfuric acid (H₂SO₄).
• NO₂ dissolves in rainwater to form nitric acid (HNO₃).

Last updated 18-07-2026 by NA

Explanation

Heavy water, also known as Deuterium Oxide (D₂O).

It is used as a neutron moderator in nuclear reactors.

Due to its ability to slow down neutrons without absorbing them.