The pattern of Irene’s increase in stature is sometimes called “line crossing” and is considered to be a very important observation in the investigation of a child’s development. Why is this term...

The pattern of Irene’s increase in stature is sometimes called “line crossing” and is considered to be a very important observation in the investigation of a child’s development. Why is this term used, and why is it important? (Hint: plot Irene’s data on the appropriate growth chart.)