Explanation: CNG stands for Compressed Natural Gas. It is an eco-friendly fuel made primarily of methane (CH₄) and is used as an alternative to petrol and diesel. CNG burns cleanly, producing fewer pollutants and helping reduce air pollution.

Explanation: ASTROSAT is India’s first dedicated multi-wavelength space observatory launched by ISRO (Indian Space Research Organisation) on September 28, 2015. It is designed for astronomy research and studies celestial objects like stars, galaxies, black holes, and neutron stars in different wavelengths — including visible, ultraviolet, and X-ray bands. ASTROSAT helps scientists study high-energy astrophysical phenomena and provides data comparable to international missions such as NASA’s Hubble Space Telescope.

Explanation: Opium is obtained from the latex present in the unripe capsule of the poppy plant (Papaver somniferum). The latex is collected by making incisions on the capsule, and after drying, it forms raw opium, which contains alkaloids like morphine and codeine.

Explanation: A concave mirror can produce an image that is larger than the object when the object is placed between the mirror’s pole and its focal point. This property makes concave mirrors useful in applications like shaving mirrors and makeup mirrors, where magnified images are needed.

The full form of LAN is Local Area Network. It is a network that connects computers and devices within a limited geographical area such as a home, office, school, or building. LANs enable data sharing, resource sharing (like printers or internet connections), and communication between connected devices. Common technologies used in LANs include Ethernet and Wi-Fi.

Other options (for context)

• Line Area Network: Incorrect — not a recognized networking term.
• Linear Area Network: Incorrect — there is no such standard network type.
• Land Area Network: Incorrect — misinterpretation of LAN abbreviation.

William Harvey, an English physician, discovered the process of blood circulation in 1628. He demonstrated that the heart acts as a pump to circulate blood continuously throughout the body via a closed system of arteries and veins. His work, published in "De Motu Cordis" (On the Motion of the Heart and Blood), laid the foundation for modern cardiovascular physiology.

Other options (for context)

• Mary Anderson: Invented the windshield wiper, not related to medicine.
• Virginia Apgar: Developed the Apgar score for assessing newborn health.
• Robert Feulgen: Discovered a staining technique for DNA, not blood circulation.

The Stockholm Convention is not associated with the reduction of greenhouse gases. It focuses on eliminating or restricting the production and use of persistent organic pollutants (POPs) — toxic chemicals that remain in the environment for long periods, such as DDT and PCBs. It does not directly address greenhouse gas emissions or climate change.

Other options (for context)

• Kigali Amendment to the Montreal Protocol: Aims to phase down the use of hydrofluorocarbons (HFCs), which are potent greenhouse gases used in refrigerants — hence it helps reduce global warming.
• Kyoto Protocol: An international treaty adopted in 1997 to reduce greenhouse gas emissions by developed countries, directly targeting climate change.