Final answer:
Primitive meteorites can be recognized by their composition which resembles that of rocks from early asteroid lava flows, containing gray silicates, metallic grains, and in some cases, organic molecules indicative of minimal alteration since the solar system's formation.
Step-by-step explanation:
Primitive meteorites are distinguishable from other meteorites and terrestrial rocks primarily due to their composition, which has remained largely unchanged since the formation of the solar system. These meteorites, unlike the differentiated ones such as the irons, stony-irons, or some types of stones, have not undergone the significant heat or pressure that would cause a separation of materials by density. Primitive meteorites are often connected to certain types of asteroids known as carbonaceous, or C-type, asteroids, located in the outer asteroid belt. These meteorites contain light-colored gray silicates with metallic grains and can include carbon, complex organic molecules, and occasionally, chemically bound water, indicating a lack of significant alteration since their origin. Therefore, the answer to the student's question is:
b. resemble the composition of rocks from lava flows that occurred on asteroids very shortly after the formation of the solar system.