Final answer:
The statement is true; meteorites are relatively unaltered planetesimals that serve as chemical fossils, providing critical information about the formation and early history of the solar system 4.5 billion years ago.
Step-by-step explanation:
The statement that meteorites offer valuable clues to the early history of the Earth and solar system because most of them are relatively unaltered planetesimals left over from the formation of the solar system is true.
Meteorites, as cosmic debris, mostly coming from asteroid fragments, preserve their original composition and thus represent relatively unmodified material dating back to the formation of the solar system 4.5 billion years ago.
The most primitive meteorites, like the carbonaceous meteorites Murchison and Allende, contain organic (carbon-rich) molecules that provide insights into the chemistry of the early solar system.
Consequently, they act as chemical fossils, offering evidence that helps scientists understand a time that has been erased on larger worlds like Earth due to geologic activity and atmospheric processes.