The sentence that does not have an error in subject and verb agreement is, "Lemonade and iced tea mixed together is a refreshing drink". As you notice it, the subject of the sentence is "lemonade and iced tea", but takes the singular form of the verb. It is because the words "lemonade and iced tea" only refers and describes one thing, which is the word "drink".
With communication we can hear and see the life of others. With communication we can knock down barriers by coming to an understanding, a middle ground if you want to call it that.
