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

• The cornea is the transparent, curved outer layer at the front of the eye.
• It helps focus light entering the eye.
• It protects the iris, pupil, and other internal parts of the eye.
• The cornea does not contain blood vessels but has many nerve endings.

Last verified on 02-09-2026

Explanation

• The kidney was the first human organ to be successfully transplanted.
• The first successful living-donor kidney transplant was performed on December 23, 1954.
• It was performed by Dr. Joseph Murray and his team in Boston, USA.
• The transplant was between identical twins, Ronald and Richard Herrick.

Last verified on 02-09-2026