Lexie Enjoys Talking to Her Infant Sister Brianna

Multiple Choice

Lexie enjoys talking to her infant sister Brianna.Lexie explains that she is three years old and holds up three fingers,then asks Brianna if she can do the same thing.Brianna waves her arms but doesn't seem to have much control over her finger movements.In words Lexie can understand her father explains that this is due to the ________________ principle.

A) cephalocaudal
B) proximodistal
C) sensorimotor
D) maturation