Explanation: Sulphur dioxide (SO₂), which is released from industrial activities and vehicle emissions, reacts with moisture in the air to form sulfuric acid, leading to acid rain. Acid rain contributes to the deterioration and discoloration of the marble of the Taj Mahal.

Explanation: The amount of blood in the human body is typically around 7% of a person's total body weight. This percentage can vary slightly based on individual factors such as age, sex, and overall health. Here’s how it breaks down: For an average adult: Blood constitutes approximately 7% of body weight. For example, if someone weighs 70 kg (about 154 lbs), they would have around 4.9 liters (about 1.3 gallons) of blood. Why this percentage? Blood volume is crucial for maintaining various physiological functions, including oxygen transport, nutrient delivery, waste removal, and regulation of body temperature. Variability: Blood volume can vary based on factors like body composition and fluid levels. Pregnant women, for instance, may have a slightly higher blood volume due to increased blood flow requirements. This percentage is a general estimate and helps in understanding the proportional relationship of blood to overall body weight.

Explanation: Heavy water (D₂O) has a higher boiling point and freezing point compared to ordinary water (H₂O). Specifically: Boiling point: Heavy water has a boiling point of about 101.4°C, which is higher than the boiling point of ordinary water (100°C). Freezing point: Heavy water has a freezing point of about 3.8°C, which is lower than the freezing point of ordinary water (0°C). Density: Heavy water is denser than ordinary water. Heavy water does not inherently produce corrosion, but its physical and chemical properties differ from those of ordinary water due to the presence of deuterium instead of hydrogen.

Explanation: Uranium-235 (U-235) is the isotope that is commonly used as fuel in nuclear reactors and for the production of atomic energy. It is fissile, meaning it can sustain a nuclear chain reaction. U-238, U-234, and U-236 are other isotopes of uranium, but U-238 is more abundant and is used in breeder reactors, while U-234 and U-236 are less commonly used in nuclear energy production.

Explanation: Kala-azar, also known as visceral leishmaniasis, is caused by the protozoan parasites of the genus Leishmania and is transmitted by the bite of infected female Phlebotomus sandflies.

Explanation: John Shepherd-Barron is widely recognized for his role in developing the first functional ATM. He introduced the concept in the 1960s, and the first ATM was installed by Barclays Bank in London in 1967.