Your friend's baby was sleeping through the night a couple of months earlier. Now she is waking up quite a bit at night. This is not only frustrating, but also concerning. She knew that you took a developmental course and wants to know if you have any ideas. What do you tell her?

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.

answer; existed; limited;

i believe the answer is: true

our brain need to reach a certain level of development   before it could interpret and understood sound with high difficulties. to proof this, we just need to pay attention in musical preference between children and adults. it is far less likely that children would enjoy things such as orchestra or rock band as much as adults due to the difference in this ability.