Science and Technology: Missiles, Space & Health

With an average heart rate of 70-72 beats per minute, the human heart beats about 35-38 million times per year. At 72 bpm: 72 × 60 × 24 × 365 = 37,843,200 beats annually.

Most heart attacks occur between 8-9 AM due to the natural morning surge in blood pressure and cortisol levels. This is part of the body's circadian rhythm that increases cardiovascular stress in the morning hours.

Skylab was the first US space station, launched in 1973. It was used for experiments in Earth sciences and microgravity research before re-entering in 1979. ISS came later (1998), Atlantis was a shuttle, and Gemini was a 1960s program.

Columbia was the first Space Shuttle to fly in space on mission STS-1 in April 1981. Challenger was the second shuttle to fly, while Discovery and Atlantis came later in the program.

Perigee specifically refers to the point in an object's orbit where it is closest to Earth. Apogee is the farthest point, while quadrature and conjunction refer to different positional relationships.

Halley's comet has an orbital period of about 75-76 years, making its returns predictable and historically significant. The other options are far too short or long for its actual cycle.

Alexei Leonov performed the first spacewalk on March 18, 1965, during the Voskhod 2 mission. Alan Shepard was the first American in space, while Eileen Collins was the first female shuttle commander.

The Hubble Space Telescope was launched on April 24, 1990, aboard the Space Shuttle Discovery. It has provided unprecedented views of the universe for over 30 years.

Salyut 1, launched by the Soviet Union in 1971, was the world's first space station. Skylab was NASA's first station, while Mir was a later Soviet station, and ISS is the current international station.

Valentina Tereshkova became the first woman in space on June 16, 1963, aboard Vostok 6. Sally Ride was the first American woman in space, while Christa McAuliffe was a teacher who died in the Challenger disaster.

Earth's average distance from the Sun is about 93 million miles, which is defined as one astronomical unit (AU). Mars is farther (~142 million miles), while Mercury and Jupiter are much closer or farther respectively.

The Agni missile was first tested in 1989 at Chandipur-on-sea, located in Odisha (then Orissa). Chandipur is an integrated test range operated by the Defence Research and Development Organisation (DRDO) for missile testing. The other options are not missile test facilities.

Agni I, a nuclear-capable ballistic missile, was successfully test-fired from the Integrated Test Range at Bhadrak, Orissa in October 2007. This test was part of India's strategic missile development program. The other months are incorrect for this specific test launch.

The Indian Air Force completed the user trials for the Akash missile system in December 2007. Akash is a medium-range surface-to-air missile developed by DRDO. The trials were conducted to validate the missile's operational readiness before induction into the IAF.

Surya is the reported codename for India's first ICBM development program. It's an intercontinental ballistic missile project that India is said to be developing as part of its strategic missile capability. The name Surya follows India's convention of naming missiles after celestial bodies and mythological figures.

Nag is India's third-generation anti-tank guided missile. The 45th test firing on March 19, 2005 was conducted at the Army's Proof & Experimental Establishment (PXE) located in Ahmednagar, Maharashtra. This facility is used for testing various weapons systems.

Nag is India's third-generation 'fire-and-forget' anti-tank guided missile. It uses top-attack capability to defeat enemy tanks and can be launched from various platforms including helicopters and land-based vehicles. The other options are not the correct missile name.