Explanation: Humans first landed on the Moon on July 20, 1969, during NASA’s Apollo 11 mission. American astronauts Neil Armstrong and Edwin “Buzz” Aldrin became the first and second humans to walk on the Moon, while Michael Collins orbited above in the command module. Neil Armstrong’s famous words, “That’s one small step for man, one giant leap for mankind,” marked this historic achievement in space exploration.

Explanation: Chikungunya is a viral disease caused by the Chikungunya virus, which belongs to the Togaviridae family. It is transmitted to humans through the bite of infected Aedes aegypti and Aedes albopictus mosquitoes. The disease causes sudden fever, joint pain, headache, and rash. In contrast, cholera (caused by Vibrio cholerae), typhoid (by Salmonella typhi), and tuberculosis (by Mycobacterium tuberculosis) are all bacterial diseases.

The pale yellow colour of urine is due to the presence of the pigment Urochrome. Urochrome is a waste product formed from the breakdown of hemoglobin in red blood cells. It is produced when hemoglobin is metabolized into urobilin and then excreted through urine. The intensity of the yellow color can vary depending on hydration levels — darker urine indicates dehydration, while pale urine indicates proper hydration.

Other options (for context)

• Urophyll: No such pigment exists in human physiology.
• Chlorophyll: Green pigment found in plants, not in urine.
• Chloroplast: Cell organelle in plants where photosynthesis occurs, not a pigment.

Explanation: The thyroid gland is the largest endocrine gland in the body. It is a butterfly-shaped gland situated in the neck region, just below the larynx. It secretes the hormones thyroxine (T₄) and triiodothyronine (T₃), which control metabolism, growth, and energy utilization. The thyroid also produces calcitonin, which helps regulate calcium levels in the blood.

Functions of the Thyroid Gland:

• Regulates metabolic rate (BMR)
• Influences growth and development
• Maintains body temperature and energy balance
• Regulates calcium metabolism via calcitonin

Disorders:

• Hypothyroidism: Leads to goitre, myxedema, or cretinism
• Hyperthyroidism: Leads to weight loss, anxiety, and increased heart rate

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.

Explanation: The full form of OMR is Optical Mark Recognition. It is a technology used to detect marks made on specially designed paper forms, such as answer sheets in competitive exams or surveys. Candidates mark their answers by filling bubbles with dark ink or pencil, and the OMR scanner reads these marks by detecting reflected light. This process allows for fast, accurate, and automated data collection without manual checking, minimizing human errors and saving time.

Explanation: The major cause of global warming is the increasing concentration of carbon dioxide (CO₂) in the atmosphere. CO₂ is a greenhouse gas that traps heat radiating from the Earth's surface, preventing it from escaping into space — a phenomenon known as the greenhouse effect. Human activities such as the burning of fossil fuels, deforestation, and industrial emissions have significantly increased CO₂ levels, leading to a rise in the Earth’s average temperature, melting of glaciers, rising sea levels, and climate change.