Explanation: Web pages are written using HTML (HyperText Markup Language). It is the standard language used to create and structure content on the web by defining elements such as headings, paragraphs, links, images, and tables.

Explanation: The decibel (dB) is a unit used to measure the intensity or loudness of sound. It expresses sound level on a logarithmic scale relative to a standard reference intensity of 10^-12 watt/m², which is the faintest sound the average human ear can hear. Normal conversation is around 60 dB, city traffic about 80–90 dB, and sounds above 120 dB can cause pain or hearing damage. The decibel scale helps compare very large variations in sound intensity conveniently.

In India, the most widely used form of renewable energy is Solar Energy. Due to the country’s tropical location, India receives abundant sunlight throughout the year, making solar power a highly viable and sustainable energy source. It is harnessed using solar panels for electricity generation and heating applications under initiatives like National Solar Mission.

• Geothermal energy: Used only in limited pilot projects.
• Hydro-electric energy: Important but not as rapidly expanding as solar.
• Thermal energy: Usually refers to non-renewable coal-based power plants.

Explanation: The S.I. unit of electric current is the Ampere (A). It is defined as the rate of flow of electric charge through a conductor. One ampere equals one coulomb of charge passing through a point in one second.

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: The full form of USB is Universal Serial Bus. It is a standard interface used to connect devices such as keyboards, mice, flash drives, and printers to a computer. USB allows data transfer and power supply between connected devices.

Swine Flu is caused by the H₁N₁ virus, a subtype of the Influenza A virus. It primarily affects the respiratory system and is transmitted from person to person through droplets from coughs or sneezes. Symptoms include fever, cough, sore throat, body aches, and fatigue. The H₁N₁ pandemic in 2009 was declared a global health emergency by the World Health Organization (WHO).

Other options (for context)

• Dengue: Caused by the Dengue virus, transmitted by Aedes mosquitoes.
• AIDS: Caused by the HIV (Human Immunodeficiency Virus), not H₁N₁.
• Bird flu: Caused by the H5N1 virus, not H₁N₁.