已知f(x)是定义域在(0,+∞)上的单调递增函数.且满足f(6)=1.f(x)﹣f(y)=f( xy )(x>0,y>0).则不等式f(x+3)<f( 1x )+2的解集是____.
—Does your father go to work by _______ car every day?
—No, he sometimes takes _______ bus.
染色体存在于 ( )中