What area of the brain associated with attention and concentration is completely myelinated by the time a child is five years of age?

Reticular formation is the area of the brain associated with attention and concentration that is completely myelinated by the time a child is five years of age. This is related with the growing attention span of the children as they are preparing to go to school,

that would be called plucking : )

explanation:

''plucking, also referred to as quarrying, is a glacial phenomenon that is responsible for the erosion and transportation of individual pieces of bedrock, especially large "joint blocks". as a glacier moves down a valley, friction causes the basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock."