Explanation

• The Doppler Effect is the change in the observed frequency of sound due to the relative motion between the source and the observer.
• If the source and observer move toward each other, the observed frequency increases.
• If they move away from each other, the observed frequency decreases.
• A common example is the changing pitch of an ambulance siren as it passes by.

Last verified on 02-09-2026

Explanation

Explanation

• DNA stands for Deoxyribonucleic Acid.
• DNA is a biological molecule found in all living cells.
• It carries genetic information from parents to offspring.
• It controls growth, development, and body functions.
• DNA is present in the nucleus of cells (mainly in chromosomes).
• It is made of nucleotides arranged in a double helix structure.
• It was discovered by James Watson and Francis Crick (1953 structure model).

Last verified on 01-06-2026

Explanation

• Main Cause: Freon / CFCs
• Effect: Breaks down O₃ molecules → more UV-B radiation
• Other Contributors: Halons, carbon tetrachloride
• Result: Skin cancer, cataracts, climate impact

• The Montreal Protocol (1987) aimed to reduce CFC emissions
• Ozone layer protects Earth from harmful ultraviolet rays

Explanation

• Liver produces bile, which helps in digestion of fats in the human body.
• Bile is a digestive fluid essential for fat breakdown.
• It is produced continuously by the liver.
• It is stored and concentrated in the gallbladder.
• It is released into the small intestine during digestion.

Last verified on 08-06-2026

Explanation

• Ibn al-Haytham presented the theory of reflection and refraction of light.
• He is also known as Alhazen.
• His work, particularly his "Book of Optics", is titled Kitab al-Manazir, written during 1011–1021.
• Born: c. 965 (c. 354 AH) Basra, Buyid Emirate
• Died: c. 1040 (c. 430 AH)[1] (aged around 75) Cairo, Fatimid Caliphate

Last verified on 02-09-2026

Explanation

• The skin is considered the largest organ of the human body.
• It covering an area of about 1.5-2 square meters (16-22 square feet).
• It weighing around 3-4 kilograms (7-9 pounds).

Last verified on 01-09-2026

Explanation

• Phosphorus is not among the top 10 most abundant elements in the Earth's crust.
• Most abundant element in Earth crust is Oxygen.
• Oxygen in the crust is (46. 1%).
• The chemical formula of oxygen (dioxygen) is O2.

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

Last verified on 01-09-2026

Explanation

• The main reaction occurring in the Sun's core is nuclear fusion.
• In fusion, hydrogen nuclei combine to form helium, releasing a huge amount of energy.
• This energy is responsible for the Sun's light and heat.
• The Sun's primary fusion process is the proton–proton chain reaction.

Last verified on 01-09-2026

Explanation

• Ammonia is produced by the Haber process.
• The reaction is: N₂ + 3H₂ ⇌ 2NH₃.
• There are 4 moles of gas on the left and 2 moles on the right.
• Increasing pressure shifts the equilibrium toward ammonia.
• Therefore, higher pressure increases ammonia production.