Because young children do not organize their attention or perceptions

POE:

A) This choice changes the meaning, because it says adults also do not organize their attention or perceptions. But the point of the sentence is to convey contrast between children and adults.
C) This choice is wrong for two reasons. 1) we need to show contrast between children and adults and 2) AS is only used for clauses not nouns
E) same as D, but worse because children is plural and you would need ADULTS to maintain parallelism

We have B and D remaining:
B) Incorrect because Like/Unlike is used to compare nouns and we have to show contrast between what children DO and what adults DO.
D) If we plug everything back into the sentence it would read "Because young children do not organize their attention or perceptions systematically, as adults [organize their attention or perceptions], they may notice and remember details that their elders ignore.

Correct answer: D