The selfishness of humans is a central assumption of orthodox ( 传统的 ) economics, where it is thought to lead to benefits for the economy as a whole．It is what the 18th-century Scottish economist Adam Smith described as the " invisible hand"But evolutionary biologists have come to see cooperation and selflessness as a big part of our___1____as a species． During the course of our evolution, they point out, cooperative groups____2___outcompeted groups of cheats. 
    So we are inherently cooperative when operating within our own groups．We have also___3____social mechanisms to reinforce actions that benefit the group．"You could say teamwork at the scale of small groups is the signature___4___of our species," says evolutionary biologist David Sloan Wilson from Binghamton University in New York. 
    But____5___teamwork can include a competition mechanism to promote actions that benefit the group, particularly in larger groups．It's also important to remember that in-group cooperation evolved partly in response to competition between groups. 
    This evolutionary perspective is radically new to economics, and it could be relevant to grand-scale economic problems that require solutions involving cooperation between nations．Take the challenge of getting nations to work together over economic solutions to climate change--a___6__focus in the run- up to climate negotiations in Paris, France, later this year．This is a gargantuan ( 巨大的 ) problem f~om any perspective, but it is___7___an issue of coordination for the sake of the common good at a massive scale, says Wilson．"The challenge is therefore to____8___at larger scales the coordination and control that takes place more spontaneously at smaller scales," he says--from multicellular( 多细胞的 ) organisms to village-sized groups of humans. 
"Morality evolved out of cooperation within and competition between groups, so when acting as a single group to tackle global problems we will have to____9___the role of natural selection ourselves," Vrflson says．This might involve pursuing a wide variety of____10___, identifying those that work best, and then creating incenfives to cooperate on implementation．"In some ways it's the opposite of the invisible hand．" 
A．adaptation 
B．assume 
C．compel 
D．consistently 
E．developed 
F．effective 
G．essentially 
H．Implement 
I．particular 
J．promptly 
K．remarkable 
L．rumor 
M．strategies 
N．success 
O．suspicion