Explanation

• Meristematic cells are generally without a large vacuole.
• They are actively dividing cells found in the growing regions of plants.
• Their cytoplasm is dense, and they have a prominent nucleus.
• Large vacuoles develop as plant cells mature.

Last verified on 02-09-2026

Explanation

• The kidneys purify the blood in the human body.
• They remove waste materials and extra water.
• Kidneys help maintain the body’s chemical balance.
• Each person has two kidneys.
• They produce urine as a waste product.

Last verified on 07-06-2026

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