— How cold the weather is! I wonder how the crops survive under such heavy snow?

— Don't worry. There is a lot of air in loose snow which _____ the cold. [ ]

A. holds back

B. holds up

C. keeps away

D. keeps out

建筑消防设施管理制度和操作规程应当由（）制定。

A.各级人民政府

B.行政管理部门

C.公安机关消防机构

D.建筑消防设施的产权单位