What is the grammer error in this : it is very important to train your dog. it keeps your dog’s mind active, and it to build an understanding between you and your dog. often owners will shout at their dogs or even punish them when what is needed is effective training

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. 

Hospital, bank, museum, cinema,park,restaurant