I believe the answer is Shaping.
Shaping is a reinforcement technique which use a reward that given gradually after the subject is showing a certain desired traits.
On parakeets, this could be done by giving them a food reward everytime they move their head closer to the place where we want it to be (closer to your cheek)
Either C or D (I think its C) but I'm not sure
The correct answer to this open question is the following.
Although you did not attach options for this question, we can comment on the following.
The two events which ended the time of primitive society started the time of animal husbandry society were the end of humans being nomads and the beginning of the Neolithic Revolution.
When humans established between the Rivers Tigris and Euphrates, in the Middle East, they formed the first and oldest civilization on planet Earth: the Sumerians.
There, they developed new and advanced agriculture techniques and could prosper learning the times of the flooding of the rivers. That flooding left a very fertile soil to grow crops. That is why they could establish powerful city-states such as Lagash, Ur, Kish, Nippur, Uruk, or Eridu.
The Neolithic Revolution is also known as the Agriculture Revolution. That is when Sumerians started to plant seeds and domesticate animals.
It was just very quiet.
Hope I helped :)
