Question

while researching a topic, a student has taken the following notes:

• planetary scientists classify asteroids based on their composition.
• c - type asteroids are composed primarily of carbon.
• they account for roughly 75 percent of known asteroids.
• s - type asteroids are primarily made up of silicate minerals.
• they account for roughly 17 percent of known asteroids

the student wants to emphasize a difference between c - type and s - type asteroids. which choice most effectively uses relevant information from the notes to accomplish this goal?
a planetary scientists classify asteroids into types, two of which are the c - type and the s - type.
b planetary scientists consider an asteroids composition (such as whether the asteroid is composed mainly of silicate minerals or carbon) when classifying it.
c roughly 17 percent of known asteroids are classified as s - type asteroids; another percentage is classified as c - type asteroids.
d c - type asteroids are mainly composed of carbon, whereas s - type asteroids are primarily made up of silicate minerals.

Explanation:

• Option A only mentions classification into C - type and S - type without emphasizing the difference.
• Option B focuses on the classification basis (composition) rather than the difference between C - type and S - type.
• Option C gives percentages but does not clearly state the difference in composition.
• Option D clearly states the difference in composition: C - type is mainly carbon and S - type is mainly silicate minerals.

Answer:

D. C - type asteroids are mainly composed of carbon, whereas S - type asteroids are primarily made up of silicate minerals.