Answer:
b . The author explains the similarities and differences in characteristics between asteroids, comets, and meteors.
Step-by-step explanation:
In the excerpt above, the author succinctly explained the individual characteristics of asteroids, comets, and meteors and he made comparisons between them. He explained the nature of their respective orbits, their nomenclature, size, the distances between them, the impact they make after hitting the earth, their composition, and the way they are named after discovery.
Given these details from the excerpt, it can be deduced that the text structure of the article shows the author explaining the characteristics of these three rocks.