Answer: D. the origin of bipedal walking in our hominid ancestors is more important than variation in genes for disease-susceptibility among modern people
Positive reinforcement is based on two facts about human nature: people appreciate recognition, and they B<span>. WANT TO KNOW HOW WELL THEY ARE DOING. Hope this helps!</span>
<span>Leon Botstein suggests that the American high school is obsolete and should be abolished because of the artificial intensity of a world defined by insiders and outsiders, in which the insiders hold sway because of superficial definitions of good looks and attractiveness, popularity and sports prowess.</span>
The alternatives here are the command economy and a (pure) market economy.
The US economy is not a comman market economy because most of it is not centrally planned, as was the case in the Soviet Union.
However, The US economy is not a pure market economy because some of it is centrally regulated, for example certain substances are forbidden.
