I agree with Isp. This case is the exception, not the rule, because majority is a collective noun. The verb must agree with the subject, not with the object of the preposition. And in fact, in this sentence the word "services" is not being described. Instead, "services" is part of a phrase that describes the subject "majority" (what majority? --majority of services) and the verb ALWAYS describes the subject, not the noun closest to it. So in this case, we are treating the collective noun 'majority' as a plural. Collective nouns confuse the heck out of me, so here's another example.
The group was playful.
The group of monkeys was playful.
The monkeys were playful.
So it seems to me that collective nouns can be singular or plural, depending on what sounds right or what sense the noun has. Please feel free to correct me on this if I'm wrong...
Okay, now to firmer ground. Question sentences are deceiving because they're constructed in an odd order. Take te gato's example. "How many students are there in your class?" 'How' and 'many' are modifiers. The subject is 'students', therefore the verb 'to be' must agree with 'students' -- 'are'. Same way with sentences starting with 'there'. "There are thirty students." The subject is still 'students' and the actual mental construction is "Thirty students are there". 'Thirty' and 'there' are both modifiers.
Okay, this is confusing, but I'm posting it anyway since I already went through all the mental gymnastics to get it typed out.
