题目

Getting older No one really knows how and why people change as they get older. Also, no theory sufficiently explains all the changes of the aging process. Aging is a complex and varied process that varies in how it affects different people and organs.   36    At a certain point in our lives our body systems will begin to weaken.    37    . It may become more difficult for us to see and hear. The slow change of aging causes our bodies to lose some of their ability to bounce back from disease and injury. In order to live longer, we have always tried to slow or stop this ch---- Are these your _______? ---- Yes, they’re my uncle’s sons.A．sisters B．cousin C．cousins D．brother