Oil Coal and Natural Gas are the fossil fuels the USA has the most reserves of. Given that only one of them is on the answers Coal is the correct answer.
        
                    
             
        
        
        
True. 
Tertiary sources compile and summarize secondary sources. Examples: reference publications such as encyclopedias, bibliographies, or handbooks
        
             
        
        
        
A geologist studies rocks and such
        
             
        
        
        
I would say D. small intestine
If you want an explanation, here it is
After leaving the stomach, water is absorbed mostly in the early segments of the
small intestine, the duodenum, and the jejunum. A small portion of all water absorption occurs in the stomach and the colon: the small intestine absorbs 6.5L/day, whereas the colon absorbs 1.3L/day.
        
                    
             
        
        
        
An area that was covered by a glacier
Primary succession is a method of bringing about fertility in infertile land that can not be cultivated. This method usually involves plant species known as "pioneer species", that do not rely heavily on soil nutrients but add nutrients to the soil. The land under the glacier is likely to be void of nutrients and infertile, so primary succession will be needed there the most.