Explanation: Mucor is not a biofertilizer; it is a saprophytic fungus that grows on decaying organic matter. Biofertilizers are living microorganisms that enhance soil fertility by fixing atmospheric nitrogen or solubilizing nutrients. Examples include Rhizobium, Azotobacter, and Anabaena.

Explanation: Prithvi was the first indigenously developed missile of India, designed under the Integrated Guided Missile Development Programme (IGMDP) launched in 1983 by the Defence Research and Development Organisation (DRDO). It is a surface-to-surface short-range ballistic missile (SRBM) capable of carrying both conventional and nuclear warheads. The Prithvi missile series includes Prithvi-I (Army version), Prithvi-II (Air Force), and Prithvi-III (Navy), with ranges varying from 150 km to 350 km.

Explanation: Although most non-metals do not conduct electricity, graphite is an exception. In graphite, each carbon atom is bonded to three others, leaving one free electron that moves freely between layers, allowing it to conduct electricity efficiently.

Explanation: Sound waves are not electromagnetic waves; they are mechanical waves that require a material medium (like air, water, or solids) for propagation. In contrast, radio waves, X-rays, and visible light are electromagnetic waves that can travel through a vacuum.

Explanation: Marijuana is a psychoactive drug obtained from the female inflorescence (flowering tops) of the Cannabis sativa plant. It contains the active compound tetrahydrocannabinol (THC), which affects the central nervous system and alters mood and perception.

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: Electrons are negatively charged particles that revolve around the nucleus in fixed paths called orbits or shells. The nucleus contains positively charged protons and neutral neutrons, and most of the atom’s mass is concentrated in the nucleus.

Explanation: Mars is known as the Red Planet because its surface contains a large amount of iron oxide (rust), which gives it a reddish appearance. It is the fourth planet from the Sun and has two moons — Phobos and Deimos.

Marble is not an element; it is a metamorphic rock composed primarily of calcium carbonate (CaCO₃). It forms when limestone is subjected to high pressure and temperature, causing recrystallization. Being a compound and mixture of minerals, marble does not consist of a single type of atom, unlike elements.

Other options (for context)

• Oxygen (O₂): A chemical element essential for respiration and combustion.
• Nitrogen (N₂): A chemical element that makes up about 78% of Earth’s atmosphere.
• Hydrogen (H₂): The lightest chemical element and the main component of stars.

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.