Explanation: White lung disease, scientifically known as byssinosis, is an occupational lung disorder caused by prolonged inhalation of cotton dust in textile and cotton processing industries. The inhaled dust irritates the airways, leading to symptoms such as chest tightness, cough, wheezing, and shortness of breath. Long-term exposure can result in chronic bronchitis and reduced lung capacity.

Preventive Measures:

• Proper ventilation and dust control in textile mills
• Use of protective masks by workers
• Regular health check-ups and dust monitoring

Explanation: Oceans contain the maximum amount of carbon dioxide (CO₂) on Earth. They act as the largest carbon sink, absorbing CO₂ from the atmosphere and storing it in dissolved form or as carbonates. This helps regulate the global carbon cycle and maintain atmospheric balance.

Explanation: The branch of science that deals with the study of the production, behavior, and effects of materials at very low temperatures is called Cryogenics. The word comes from the Greek words “kryos” meaning cold and “gen” meaning to produce. Cryogenics involves cooling substances to temperatures below −150°C (123 K). It has applications in liquefying gases (like oxygen and nitrogen), cryopreservation of biological samples, superconductivity research, and rocket fuel storage (e.g., liquid hydrogen and oxygen).

Explanation: A modem (short for modulator-demodulator) is a device that enables computers to communicate with each other over telephone lines. It converts digital signals from a computer into analog signals for transmission and then back into digital form at the receiving end.

Explanation: In space, where there is no gravity, convection cannot occur because it depends on the movement of fluid due to gravity-induced density differences. Therefore, heat transfer in such conditions takes place only through radiation and conduction (within the liquid itself).

Explanation: The term "Ozone hole" does not mean an actual hole but refers to a significant decrease in the thickness of the ozone layer in the Earth's stratosphere. This thinning occurs mainly over the Antarctic region during spring (September–November) due to chemical reactions involving chlorofluorocarbons (CFCs) and other ozone-depleting substances. These chemicals release chlorine and bromine atoms, which destroy ozone (O₃) molecules. The thinning allows more harmful ultraviolet (UV) radiation to reach the Earth's surface, causing health and environmental hazards.

An Atom bomb works on the principle of nuclear fission. In this process, the nucleus of a heavy atom such as Uranium-235 or Plutonium-239 splits into two or more smaller nuclei when bombarded with a neutron. This splitting releases a tremendous amount of energy along with more neutrons, which further cause chain reactions — leading to a massive explosion.

Other options (for context)

• Chemical reaction: Produces far less energy; used in conventional explosives, not atomic bombs.
• Nuclear fusion: Powers hydrogen bombs (thermonuclear bombs), not atomic bombs.
• Atomic collision: General term — does not describe the chain reaction mechanism in fission.