Sustainable Development refers to growth that meets the needs of the present without compromising the ability of future generations to meet their own needs. It aims to balance economic progress, social equity, and environmental protection by conserving natural resources and reducing pollution for long-term ecological stability.

• Green economy: Focuses mainly on eco-friendly industries.
• Holistic development: Emphasizes overall human and social growth.
• Subsistence agriculture: Involves farming mainly for self-consumption.

Explanation: The time period of a simple pendulum is given by the formula T = 2π√(L/g), where L is the length of the pendulum and g is the acceleration due to gravity. Since the Moon’s gravity is about 1/6th of Earth’s, the value of g decreases, causing the time period to increase.

Explanation: The troposphere is the lowest layer of the Earth's atmosphere and is closest to the Earth's surface. It extends up to about 8–15 km from the surface, depending on latitude and season. This layer contains about 75% of the total atmospheric mass and almost all the water vapor and weather phenomena such as clouds, rain, and storms occur here. The temperature decreases with increasing altitude in this layer. The boundary between the troposphere and the stratosphere is known as the tropopause.

Explanation: ELISA stands for Enzyme-linked immunosorbent assay. It is a biochemical test used to detect and measure antibodies, antigens, proteins, or hormones in a sample. The method relies on an enzyme-linked antigen or antibody and a color change to indicate a positive reaction.

Explanation: A microscope uses a system of convex lenses to magnify very small objects. Convex lenses, also known as converging lenses, bend light rays inward to a focal point, creating an enlarged and clear image of the specimen. A compound microscope typically contains two sets of convex lenses — the objective lens (near the specimen) and the eyepiece lens (near the observer’s eye). The objective lens forms a real, inverted, and magnified image, which is then further magnified by the eyepiece to produce a large virtual image.

Explanation: Cobalt-60 (Co-60) is a radioactive isotope of cobalt that emits high-energy gamma rays during its decay process. It decays into Nickel-60 (Ni-60) by beta decay, releasing two strong gamma photons of energies 1.17 MeV and 1.33 MeV. Due to these intense gamma emissions, Co-60 is widely used in radiation therapy (teletherapy) for cancer treatment, as well as in industrial radiography and sterilization of medical equipment. Gamma rays have high penetration power, allowing them to destroy cancerous cells deep inside tissues.

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: 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.