Which statistic is NOT useful for mapping the locations and shapes of the spiral arms of our Galaxy?

Question

Quizplus · Accepted Answer

The distribution of globular clusters is not useful for mapping the locations and shapes of the spiral arms of our Galaxy because globular clusters are not located in the spiral arms of the Galaxy. They orbit around the galactic center but do not follow the spiral arms. Therefore, their distribution would not help us with mapping the actual locations and shapes of the spiral arms. The other choices (B, C, and D) are all useful for mapping the spiral arms because they are located within or adjacent to the spiral arms. O and B stars are young, massive stars that are located in the spiral arms. Emission nebulae (H II regions) are also located in the spiral arms and are formed by hot, young stars. Giant molecular clouds are the sites of star formation and are located in the spiral arms as well.

Which Statistic Is NOT Useful for Mapping the Locations and Shapes