Ummmmmm..... Ok then.....
A mountain is a land form with high elevation. The mountain range is a group of mountains that are closely related in shape, structure, or age.
Answer:
Are
Explanation:
According to subject verb agreement rule of grammar, Singular subject should take singular verb and plural subject should take plural verb.
For example boy is eating apple--
boys are eating apple
In the sentence mentioned above first we have to identify the subject to which is/are should agree with
subject is Buildings in Helsinki which is a plural noun and hence are is the correct verb to be used with buildings.