The correct answer is easy child.
No child is undemanding - parents have to be around their baby at all times, caring for it, and tending to its every need. But this child can easily adapt to anything, which is why she doesn't really take up a lot of her parents' time, and doesn't cause problems.
Where any male age 18 and over was drafted into the military,
I believe the answer is: learning theory
Learning theories refers to the framework that explain how people obtained data/information, process it as a part of learning, and transform it into knowledge. In social settings, things such as emotion, congitive abiltiy, observation of other behaviours, and the influence of other peiople would be seen as crucial factors that affect people's learning rate.
