Neil Armstrong was the first man to land on the Moon on July 20, 1969, during NASA’s Apollo 11 mission. He became the first human to step onto the lunar surface, famously saying, "That's one small step for man, one giant leap for mankind." His historic achievement marked a major milestone in space exploration.

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• Aldrin: Refers to Buzz Aldrin, the second man to walk on the Moon, who accompanied Armstrong on Apollo 11.
• Michael Collins: The third member of the Apollo 11 crew, who orbited the Moon in the command module but did not land.
• Gagarin: Refers to Yuri Gagarin, the first human to travel into space in 1961, but he never landed on the Moon.

Explanation: Acid rain is caused by the presence of pollutant gases such as sulphur dioxide (SO₂) and nitrogen oxides (NOₓ) in the atmosphere. These gases are released mainly from burning of coal, oil, and industrial emissions. When they combine with water vapor in the atmosphere, they form sulphuric acid (H₂SO₄) and nitric acid (HNO₃), which fall to the ground as acid rain. It damages soil, plants, aquatic life, and even buildings and monuments made of marble or limestone.

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).

Graphite allows electric current to pass through it. Although it is a form of carbon, its atoms are arranged in layers with free-moving electrons, making it a good conductor of electricity. This property makes graphite useful in electrodes, batteries, and brushes of electric motors.

• Glass, Rubber, PVC: All are insulators and do not conduct electricity.

Explanation: Haemoglobin is a complex iron-containing protein found in red blood cells (RBCs). It binds with oxygen in the lungs to form oxyhaemoglobin and releases it in tissues where oxygen levels are low. It also helps transport carbon dioxide from tissues back to the lungs. This oxygen-carrying property makes haemoglobin the essential respiratory pigment in humans and most vertebrates.

Explanation: The Growth Hormone (GH), also known as Somatotropin, is secreted by the anterior lobe of the pituitary gland, which is located at the base of the brain. This hormone stimulates growth, cell reproduction, and regeneration in humans and other animals. It plays a vital role in increasing height during childhood and adolescence, regulating metabolism, and maintaining muscle and bone mass. A deficiency of GH causes dwarfism in children, while excess secretion leads to gigantism or acromegaly.

The normal body temperature of a healthy human being is approximately 37 °C, which is equivalent to 98.6 °F. This temperature is maintained through a balance between heat production and heat loss in the body. The body’s thermoregulation is controlled by the hypothalamus in the brain to ensure proper functioning of enzymes and metabolic processes.

Other options (for context)

• 98.4 °C: Incorrect — the correct equivalent in Fahrenheit is 98.6 °F, not in Celsius.
• 14.5 °C: Much lower than the human body temperature — such a value would indicate hypothermia or death.
• 25 °C: Represents a mild room temperature, not body temperature.

Explanation: Malaria and Trichomoniasis are both protozoan diseases, not bacterial. Malaria is caused by Plasmodium species (transmitted by female Anopheles mosquitoes), while Trichomoniasis is caused by Trichomonas vaginalis, a sexually transmitted protozoan infection. Unlike bacterial diseases, these are treated using antiprotozoal drugs rather than antibiotics.

Explanation: PROLOG (Programming in Logic) is a high-level programming language widely used in the field of Artificial Intelligence (AI) and computational linguistics. It is based on formal logic and is especially useful for solving problems involving pattern matching, rule-based reasoning, and natural language processing.