Answer:
The correct answer is high rates of evaporation
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
