What is the primary difference between meteoroids and meteorites?

The primary difference highlighted in the correct answer emphasizes that meteorites are pieces of debris from space that have successfully reached and impacted the Earth's surface. This distinction is vital because it indicates the transition of an object from one classification to another, based on its interaction with Earth.

Meteoroids are smaller celestial objects in space, typically ranging from the size of a grain of sand to a few meters. When these meteoroids enter the Earth's atmosphere and create a visible brightness due to friction and heat, they are referred to as meteors. If any portion of these meteoroids survives the intense heat and pressure of atmospheric entry and lands on Earth, that surviving fragment is classified as a meteorite.

Understanding this classification helps underline the dynamic journey these objects undertake and their significance in studies related to astronomy and Earth sciences. The other options either suggest misconceptions about size, survival, or formation, rather than clarifying the key transition from space to the Earth that defines meteorites.