When 1-year-old babies in an experiment were placed on an ambiguous visual cliff and saw an expression of fear on their mothers' faces, what portion of them crossed the cliff?

The answer is: None of them

For most children, we develop a functional ability to distinguish facial expression by the age of 6 or older. there are only 1 facial expression that recognized by 1-year old infants (happy and angry) , while the other complex expressions would look generally the same for them.

The adams apple, or laryngeal prominence. is a feature of the human neck, and is the lump or protrusion that is formed by the angle of the thyroid cartilage surrounding the larynx seen especially in males.