Which of the following best describes meteoroids, meteors, and comets?

• A. A meteoroid is a small rocky body in space; a meteor is a meteoroid that enters Earth's atmosphere and burns up; a comet is a body of ice and dust with a coma and tail.
• B. A meteoroid is a large planet; a meteor is a star; a comet is a meteor shower.
• C. A meteoroid is a rocks in space; a meteor is a meteor shower; a comet is a rock.
• D. A meteoroid is a sunspot; a meteor is solar wind; a comet is a satellite.

Answer: (A)

The main idea here is how these space objects are defined and what happens to them in different places. A meteoroid is a small rocky body that travels through space. When such a body enters Earth's atmosphere, it becomes a meteor and lights up as it burns due to friction with the air. If it survives the plunge and hits the ground, that piece is called a meteorite. A comet, on the other hand, is a body made mostly of ice and dust that, when it gets near the Sun, develops a glowing coma and often a long tail as the ice sublimates and dust is pushed away by solar wind.

That makes the described option the best: it correctly states meteoroids as small rocky bodies in space, meteors as meteoroids burning up in Earth's atmosphere, and comets as bodies of ice and dust with a coma and tail. The other choices mix up the objects and processes (for example, calling a meteoroid a large planet, a meteor a star, or a comet a meteor shower), which is not accurate.