人的一个染色体组中( )
A:可能存在等位基因
B:含46条染色体
C:性染色体为XX或XY
D:染色体形态、功能各不相同
食物在冰箱中能保存一定时间不腐败,是因为( )
—Didn't you see the sign "No parking!" on the right?
—Sorry, I didn't. But now I know parking ____________ here.