Cooperation in team sports help build_____.

　　定位到文中第一段的第二句，“Learning to cooperate with others towards a common goal in sports is what builds character, friendship and important life skills for players.”， 在体育中学习与他人合作是一个共同的目标，它可以培养运动员的性格、友谊和重要的生活技能。故选B。