A layer of hot rock. The upper most part of the mantle and the crust together form a rigid layer. Like a road tar softened by the heat of the sun, this part of the mantel is somewhat soft - it can bend like plastic. Is a layer of molten metal that surrounds the inner core. Is a dense ball of solid metal.
In many countries, including Canada, having smoke and carbon monoxide detectors in the house is the law. The reason is simple: these alarms save lives. Many house fires occur at night. If there is no smoke detector, those sleeping in the house may not notice the fire and will be overwhelmed by smoke.
A carbon monoxide detector or CO detector is a device that detects the presence of the carbon monoxide (CO) gas in order to prevent carbon monoxide poisoning. In the late 1990s Underwriters Laboratories (UL) changed their definition of a single station CO detector with a sound device in it to a carbon monoxide (CO) alarm.