We can say body language is the term for communication using the body movements or gestures along with sound, verbal language or other communication. It also includes the movement of the eyebrows.Body language also understand the use facial expressions.
When a person crosses his arms across the chest, this intimates that a person is putting barrier between themselves and others, this is the most basic and powerful body-language signals. When the situation is friendly, that shows that a person is thinking deeply about the discussion. But in a serious situation, it might mean that a person is opposing expressions. A blank facial expression indicates unfriendliness.
Equal eye contact shows that a person is thinking positively about what the speaker is saying. Absence of eye contact intimates negativity. Eye contact is secondary and misleading gesture because we are taught to make eye contact while speaking, right from the early age only.
Disbelief indicated by forbid gaze, or by touching ears and chin. When a person is not agreed by what someone says, the attentions also gets disappeared.
When a person leans his head on one side, or by the eyes are slighly unfocused from the speaker. Boredom is the reason for such things.
Extended eye contact and posture indicates the interest.