Dr. MacGiver believes that children who are not visually stimulated during the first four months of life will never develop normal visual perception. Obviously, Dr. MacGiver believes that this developmental stage is a:.
A. cognitive schema.
B. teratogen.
C. epigenetic mark.
D. critical period.

Critical period

Explanation:

The critical period in developmental psychology is the stage of the maturation stage. This is a critical period. In this period the stimuli do not get the information from the environment. This is a very sensitive period. In this period, there are two stages:

The strong period is more sensitive to the environment. Thus here Dr. MecGiver believes that this developmental stage is a critical period.

b) trade is easy because of the direct line between their major ports. bilateral trade reached 89,6 thousand million.

explanation:

may i ask what challenges?