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: Oncology is a branch of medical science that focuses on the study, diagnosis, treatment, and prevention of cancers and tumours. The term is derived from the Greek word “onkos” meaning mass or tumour. A specialist in this field is called an Oncologist.

Major Branches of Oncology:

• Medical Oncology: Treatment using chemotherapy, targeted therapy, and immunotherapy.
• Surgical Oncology: Removal of tumours through surgery.
• Radiation Oncology: Treatment of cancer using radiation therapy.

Common Cancers Studied in Oncology: Lung cancer, breast cancer, skin cancer, leukemia (blood cancer), and prostate cancer.

Explanation: Below the critical temperature, gases can be liquefied by applying pressure because the intermolecular forces of attraction between gas molecules become effective. These forces pull the molecules closer together, resulting in the formation of a liquid state.

Explanation: Chikungunya is a viral disease caused by the Chikungunya virus, which belongs to the Togaviridae family. It is transmitted to humans through the bite of infected Aedes aegypti and Aedes albopictus mosquitoes. The disease causes sudden fever, joint pain, headache, and rash. In contrast, cholera (caused by Vibrio cholerae), typhoid (by Salmonella typhi), and tuberculosis (by Mycobacterium tuberculosis) are all bacterial diseases.

Explanation: The Indian Space Research Organisation (ISRO) is headquartered in Bangalore (Bengaluru), Karnataka. It was established in 1969 under the guidance of Dr. Vikram Sarabhai, who is known as the father of the Indian space program. ISRO is India’s national space agency, responsible for space research, satellite launches, and planetary exploration. It developed major missions such as Chandrayaan (Moon mission), Mangalyaan (Mars Orbiter Mission), and PSLV & GSLV launch vehicles.

Explanation: The longest day in the Southern Hemisphere occurs on 22nd December, which marks the Summer Solstice in that hemisphere. On this date, the South Pole is tilted toward the Sun, resulting in longer daylight hours and shorter nights. Conversely, at the same time, the Northern Hemisphere experiences its winter solstice—the shortest day and longest night of the year. After 22nd December, the days in the Southern Hemisphere gradually begin to shorten.

Explanation: The Sinoatrial (SA) node is a specialized group of modified cardiac muscle fibers located in the right atrium of the heart, near the opening of the superior vena cava. It generates electrical impulses (action potentials) that initiate each heartbeat. Therefore, it is known as the natural pacemaker of the heart.

The impulses from the SA node spread across the atria, causing them to contract, and are then transmitted to the Atrioventricular (AV) node, Bundle of His, and Purkinje fibers to coordinate ventricular contraction.

Normal rate of SA node firing: ~70–75 impulses per minute (in a healthy adult at rest).

In case of SA node failure: Artificial pacemakers are implanted to maintain normal rhythm.

Xylem is a type of vascular tissue in plants responsible for the transportation of water and dissolved minerals from the roots to the stems and leaves. The upward movement of water through xylem vessels occurs due to processes like transpiration pull, root pressure, and capillary action. Xylem also provides mechanical support to the plant.

Other options (for context)

• Food: Transported by phloem, not xylem.
• Nutrient: Minerals are carried along with water but the primary function of xylem is water transport.
• Both food and water: Incorrect — only phloem transports food; xylem transports water.