1 AU means 1 astronomical unit or the aproximate distance from the earth to the sun 
1AU=<span>149597870.7 kiometers
1 billion=1,000,000,000
600 billion=600,000,000,000
</span>
<span>x times 1AU=600,000,000,000
x times </span>149597870.7=<span>600,000,000,000
solve for x
divide both sides by </span><span>149597870.7
</span>x=4010.75
so aprox 4011 AU's
        
             
        
        
        
Answer:
I know it is jj. The answer is maybe that. 
 
        
                    
             
        
        
        
Answer:
C) Books about the lives of inventors, explorers, and artists.
Explanation:
A biography is a book about a person's life that was written by somebody else. Option C) Books about the lives of inventors, explorers, and artists best fits this description. Therefore books in the biography genre would include books about the lives of inventors, explorers, and artists. 
 
        
                    
             
        
        
        
Channel proteins is the answer to your question
        
             
        
        
        
Answer:
The amount of CO2 found in the atmosphere varies over the course of a year. Much of this variation happens because of the role of plants in the carbon cycle. Respiration happens all the time, but dominates during the colder months of the year, resulting in higher CO2 levels in the atmosphere during those months.
Explanation: