Answer:
4) They had a rate of cognitive impairment several times higher than the children adopted at less than 6 months of age.
Step-by-step explanation:
This experiment shows how important the first months of development are in childhood. The effects of deprived nutrion, afection, and cognitve stimulation can cause serious damages. When adopting, all these conditions can improve, so the earlier a child is adopted, the best it would do to their development.
Cognitive development depends very much on emotional facts as well as on nutrional facts. A child needs the most optimal conditions to fully developed, and the earlier that is corrected, the ealier it can improve.