Environment determines where the individual falls within the range.
A genetic disorder caused by two recessive alleles that prevent the body from decomposing the amino acid phenylalanine, potentially resulting in mental retardation. In the video Physical growth and motor development , the effects of illness on an infant's health were described as circular . Describe how such effects can be circular . A reflex is NOT intentional, voluntary, or consciously undertaken. Describe their relative advantages and disadvantages.