A verb agreement question with two verbs tests whether each verb matches its own subject. Sort the choices by singular and plural forms at both positions, because both matches matter. Then find each verb’s true subject, looking past phrases and extra information. With an opening phrase before the verb, ask whether the subject comes later. Check with it or they: one thing takes a singular verb, and more than one takes a plural verb.
Hints
- Hint 1
Start with the phrase beginning Among. Ask what belongs among the features.
- Hint 2
Try the sentence in subject-first order. The words beginning that distinguish describe the features, so look past them for the main subject.
- Hint 3
Check each verb against its own subject. For the second verb, ask whether its subject names a whole group or picks out one member at a time.
Step-by-step
Find both true subjects
Step 1Sort the two verb positions
Sort the choices by singular and plural forms at both verb positions. At each position, the choices offer a singular form for one thing and a plural form for more than one, so we need two subject-verb matches. One verb follows Among the features, and the other belongs to the added part about the dots.
- Step 2
Find the subject after the first verb
What belongs among the features? The opening Among the features names a group, and the words beginning that distinguish describe which features the writer means. The opening phrase tells us where the subject belongs, so look after the first verb for its subject. Flip the order to read a sequence of tiny dots followed by the verb and then the opening phrase. The main subject is sequence, one thing, while of tiny dots tells us what it contains.
- Step 3
Find the second subject
Which subject controls the verb before beside observations of low-altitude stars? The words each of which point back to the dots. Cross out of which, and we're left with each as the subject. Each points to one dot at a time, so its verb needs a singular form even though the sequence holds several dots.
- Step 4
Test the verb pair
Which verb pair passes the short check? Replacing the subjects with shorter words gives it is and each one appears. Use is after Among the features and appears before beside observations of low-altitude stars, because each form matches its own subject. Choice A.