Explanation: ROM (Read Only Memory) retains its data even when the power is turned off, making it non-volatile memory. It stores essential programs such as the computer’s firmware or BIOS, which are required for booting the system. In contrast, RAM loses all information when power is shut down.

Explanation: In 1643, Italian scientist Evangelista Torricelli invented the barometer, an instrument used to measure atmospheric pressure. His mercury barometer demonstrated that air has weight and that atmospheric pressure can support a column of mercury in a glass tube.

Explanation: An alpha particle (α-particle) is a positively charged particle that consists of two protons and two neutrons, the same as the nucleus of a helium atom (He²⁺). It carries a +2 charge because of the two protons and has a mass number of 4. Alpha particles are emitted during the radioactive decay of heavy elements such as uranium, radium, and thorium. They have high ionizing power but low penetration ability and can be stopped by a sheet of paper or human skin.

Explanation: Adrenaline (also known as epinephrine) is secreted by the adrenal medulla in response to stress, fear, anger, or excitement. It prepares the body for “fight or flight” by increasing heart rate, blood pressure, and glucose levels, and by dilating the air passages to supply more oxygen. Because it helps the body respond instantly to emergencies, it is called the “emergency hormone.”

Explanation: Heavy water is chemically known as Deuterium oxide (D₂O). It is similar to ordinary water (H₂O), but the hydrogen atoms are replaced by deuterium — a heavier isotope of hydrogen containing one proton and one neutron. Heavy water is not suitable for drinking but is used as a moderator and coolant in nuclear reactors because it slows down neutrons, allowing a controlled nuclear fission reaction. It is also used in scientific research and isotope studies.

Explanation: The elements Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N) — collectively known as CHON — were primarily responsible for the origin of life on Earth. These elements are the basic building blocks of all biological molecules such as proteins, nucleic acids, carbohydrates, and lipids. Early Earth's atmosphere contained these elements in gaseous forms (like CH₄, NH₃, H₂, and H₂O), which combined under lightning and UV radiation to form simple organic compounds — a process explained by the Miller–Urey experiment.

Explanation: The weight of a person depends on the gravitational force exerted by a celestial body. The Moon’s gravity is only about 1/6th that of the Earth’s because it has much less mass and a smaller radius. Therefore, an object or person weighing 60 kg on Earth would weigh only about 10 kg on the Moon. Although mass remains constant everywhere, weight changes according to the local gravitational acceleration (g). Hence, lower gravity results in lower weight on the Moon.

Explanation: Nuclear fission is the process in which the nucleus of a heavy atom, such as Uranium-235 or Plutonium-239, splits into two or more lighter nuclei when bombarded by a slow-moving neutron. This reaction releases a large amount of energy, along with additional neutrons that can trigger further fission reactions—leading to a chain reaction. This principle is used in nuclear reactors for power generation and in atomic bombs for explosive energy release.

Explanation: The erythrocytes (RBCs) play a crucial role in the circulation of blood by carrying oxygen from the lungs to body tissues and returning carbon dioxide for exhalation. They contain hemoglobin, which binds oxygen and maintains the red color of blood. Circulation itself is driven by the heart and supported by these oxygen-carrying cells.

Explanation: When a sound wave travels from one medium to another, its frequency remains unchanged. However, its wavelength and speed change depending on the properties of the new medium. The constant frequency ensures that the sound maintains the same pitch.