Coal
Coal is a combustible black rock that is formed from prehistoric plant remains. Coal is formed from the anaerobic decomposition of dead plant matter such as trees, ferns, mosses and other marsh plants that grew on the earth surface over millions of years ago.  Coal is composed largely of carbon and is usually burned as a fuel.
 
        
                    
             
        
        
        
I am thinking the rock that forms from lava that cools quickly is D) Obsidian.
        
                    
             
        
        
        
Answer:  The atmosphere prevents the sudden increase in temperature during the daylight hours. And during the night, it slows down the escape of heat into outer space The atmosphere keeps the average temperature of the Earth fairly steady during the day and even during the course of the whole year.