Define.
The group of eight planets and other matter that orbits the Sun.
A. Solar system
B. Universe
C. Galaxy
D. Biosphere
A. Solar system
A. Solar system
The correct answer is A. Solar system.
To arrive at this answer, we need to understand the definitions of the options given.
A. Solar system: It refers to the collection of the Sun, eight planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune), their moons, asteroids, comets, and other celestial objects that orbit the Sun.
B. Universe: It encompasses everything that exists, including all matter, energy, galaxies, stars, planets, and everything in between.
C. Galaxy: A galaxy is a vast system of stars, stellar remnants, interstellar gas, dust, and other celestial bodies, bound together by gravitational forces.
D. Biosphere: The biosphere refers to the parts of the Earth's surface, atmosphere, and hydrosphere where living organisms are found.
Given the definition provided, the group of eight planets and other matter that orbits the Sun is specifically referred to as the solar system. Therefore, the correct answer is A. Solar system.