Nowadays the belief has become general ________ sea food and fruits rich in vitamin C should never be eaten at the same meal.
A:that
B:how
C:when
D:why
小聪和小明为了探究“温度和物质状态对同种物质密度的影响,在一定的环境下将1g的冰加热,分别记录其温度和体积的数据,利用描点法得到了如图所示的图象 。则下列说法中正确的是( )
观察一下,哪条线段是圆的半径。( )