The causes of leg pain can be musculoskeletal, neurological, or vascular. Shin splints and stress fractures can result from repetitive sports, such as running. Leg pain can sometimes indicate a serious vascular problems.
Noun. 1. altruism-the quality of unselfish concern for the welfare of others. selflessness. unselfishness-the quality of not putting yourself first but being willing to give your time or money or effort etc. for others; rural people show more devotion and unselfishness than do their urban cousins.
Mutualism or interspecies reciprocal altruism is a relationship between individuals of different species where both individuals benefit. In general, only lifelong interactions involving close physical and biochemical contact can properly be considered symbiotic.