The concept of maturation is most relevant to understanding the absence of

The correct answer should be - bladder control among 2-year-olds.
If a child still cannot control his or her bladder at the age of 2, it means that he or she still hasn't matured enough to do that. The other options are incorrect because you can be mature, and still feel secure around your family, or still lack self-esteem, or lack schemas at a particular age. 

Yes you are cute answer theories to explain the colonization of the new world the last great habitable landmass to be occupied by humans focus on the bering land bridge, or beringia, which emerge by siberia and alaska the last ice age.