The word help is incorrect because it has an error in subject-verb agreement.
Subject verb agreement happens when the subject of the verb agrees with the correct form of the verb. The subject of the verb help is it". "It" is a third person singular pronoun. In order to make help agree with the subject "it", and -s is necessary. It should say "...and it helps to build...".
Often when a verb agrees with a singular third person pronoun, it is necessary to add -s to the end of the verb. For example, It runs, It walks, It smiles. When you use first or second person pronouns there is no -s, as in: I run, You walk, I smile.
