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
A horse and a cow are two different species and therefore are not compatible :) just like a human can't have a baby with a different species... seen any duck/human's recently, probably not hey - Goodluck
A control group of the experiment is the one in which no treatment or intervention is given. So, in your case, the pea plants in which was not subjected any of the fertilizers, will serve as a control group. This is a negative control. A positive control group is the one in which an established treatment is given, which definitely leads to the production of the desired character. So, in your case, a very good well-known fertilizer which has a positive control on the growth of the pea plant, would serve as a positive control.