Simplify the following text for a Grade 16 native English-speaking person.
Original: This type of asteroid has very similar spectra to carbonaceous chondrite meteorites ( types CI and CM ) , whose chemical composition is approximately the same as the Sun and the primitive solar nebula , except that they do not contain hydrogen , helium and other volatiles .
Simplified: This type of asteroid has very similar spectra to carbonaceous chondrite meteorites ( types CI and CM ) , whose chemical make-up is about the same as the Sun and the primitive solar nebula , except that they do not contain hydrogen , helium and other volatiles .