Deciduous trees are those that shed all their leaves once a year, usually during the dry or winter season to conserve water and energy. After a period of dormancy, they grow new leaves at the beginning of the next growing season. Common examples include teak, sal, neem, and peepal. This adaptation helps the trees survive unfavorable climatic conditions.

Other options (for context)

• Coniferous trees: Mostly evergreen and do not shed all their leaves at once; examples include pine and deodar.
• Evergreen trees: Retain their leaves throughout the year and shed them gradually.
• Both deciduous and coniferous trees: Incorrect — only deciduous trees completely shed their leaves annually.

Explanation: In India, the largest share of electricity generation comes from thermal power. Thermal power plants generate electricity by using heat energy, primarily produced by burning coal, natural gas, or oil. Among these, coal-based thermal power contributes the majority. Although renewable sources like solar and hydro power are growing rapidly, thermal energy still accounts for over 70% of India’s total electricity production. This dominance is due to the abundant availability of coal and the extensive infrastructure built around it.

Explanation: AIDS, Hepatitis, and Typhoid fever are all diseases that can be spread by human beings. While AIDS and Hepatitis are viral diseases and Typhoid is a bacterial disease, all three are transmitted through contact with infected individuals or their body fluids, making human-to-human transmission common.

India’s first successful atomic device was tested at Pokhran in the Thar Desert of Rajasthan on 18th May 1974. The operation was code-named "Smiling Buddha" and was conducted by the Bhabha Atomic Research Centre (BARC) under the leadership of scientists like Dr. Raja Ramanna. This event marked India’s entry into the group of nuclear-capable nations.

Other options (for context)

• Bikaner: A city in Rajasthan, but no nuclear tests were conducted there.
• Barmer: Located near the Pakistan border, not the site of India’s nuclear test.
• Jaisalmer: Close to Pokhran geographically, but not the test location.

Adolf Gaston Eugen Fick, a German physiologist, invented the first successful contact lens in 1888. His design consisted of a glass lens that covered the entire eye, resting on the sclera (the white part of the eye). Though bulky and uncomfortable by today’s standards, it laid the foundation for modern soft and gas-permeable contact lenses used in vision correction and cosmetics.

Other options (for context)

• Enrico Fermi: Known for his work in nuclear physics and development of the first nuclear reactor.
• Sandford Fleming: Introduced the concept of standard time zones.
• Benoit Fourneyron: Invented the water turbine, not related to optics or vision correction.

Dynamite was invented by Alfred Nobel in 1867. He was a Swedish chemist, engineer, and industrialist who discovered that nitroglycerin could be stabilized by mixing it with an absorbent material like diatomaceous earth, making it safer to handle and transport. This invention revolutionized the mining and construction industries. In his later years, Alfred Nobel established the Nobel Prizes using the wealth he accumulated from his inventions.

Other options (for context)

• J. B. Dunlop: Invented the pneumatic rubber tyre.
• James Simons: A mathematician and hedge fund manager, not an inventor.
• Peter Hargreaves: Not related to any major scientific invention; possibly confused with James Hargreaves, who invented the Spinning Jenny.

Explanation: To read small letters, a convex lens (converging lens) with a short focal length such as 5 cm is used as a magnifying glass. It produces an enlarged, upright, and virtual image of the object, making tiny text appear bigger and clearer to the eye.

Explanation: Anaemia is a condition caused by a deficiency of iron in the body, leading to reduced formation of haemoglobin in red blood cells. As a result, the blood’s capacity to carry oxygen decreases, causing fatigue, weakness, dizziness, and pale skin. Iron is essential for haemoglobin synthesis, and deficiency can result from poor diet, blood loss, or malabsorption. Foods rich in iron include green leafy vegetables, liver, red meat, legumes, and jaggery.

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.