Explanation: Normal human blood has a slightly alkaline pH of 7.35 to 7.45. This pH is maintained by buffer systems such as the bicarbonate buffer system and controlled by the lungs (CO₂ regulation) and kidneys (acid-base balance). A deviation from this range can be life-threatening — acidosis occurs if pH falls below 7.35, and alkalosis occurs if it rises above 7.45.

Explanation: Natural gas is a non-renewable source of energy because it is formed from fossilized organic matter over millions of years and cannot be replenished quickly. In contrast, geothermal energy, flowing water, and biomass are renewable as they can be naturally regenerated over short periods.

Explanation: Lysosomes are known as the ‘suicidal bags’ or ‘disposal units’ of the cell because they contain powerful hydrolytic enzymes capable of breaking down worn-out cell organelles, foreign substances, and even the entire cell when it becomes damaged or diseased.

Explanation: When a ship floats on water, it displaces a volume of water whose mass is equal to the mass of the ship. This is in accordance with Archimedes’ Principle, which states that an object floats when the buoyant force (equal to the weight of displaced fluid) balances its own weight.

Explanation: Lysosomes are known as the ‘suicidal bags’ or ‘disposal units’ of the cell because they contain powerful digestive enzymes capable of breaking down worn-out cell parts, foreign substances, and even the entire cell when it becomes damaged or obsolete.

Explanation: In household electrical wiring, all the given statements are correct: the red insulated wire is the live (phase) wire, the black insulated wire is the neutral wire, and the green insulated wire is used for earthing to ensure safety by preventing electric shocks.

Explanation: The sex of a newborn baby is determined by the chromosome inherited from the father. Humans have 23 pairs of chromosomes — 22 pairs of autosomes and one pair of sex chromosomes. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The mother always contributes an X chromosome, but the father can contribute either an X or a Y. If the sperm carrying an X chromosome fertilizes the ovum, the child will be a girl (XX); if the sperm carries a Y chromosome, the child will be a boy (XY).