There are three main regions of the kidney.
<span>1.Renal cortex -  It is the outer region of the kidney which contains the renal corpuscles and the renal tubules (without the loop of Henle). It produces the erythropoietin.</span> 
<span>2.Renal medulla  - It is the innermost part of the kidney which contains the renal pyramids.</span> 
<span>3.Renal pelvis  -  It is the region that collects urine from the nephrons, thus it contains the place where ureter leaves the kidney.</span>
        
             
        
        
        
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Answer</h2>
The right option is (A).
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Explanation</h2>
The RNA gets its information from DNA to synthesise the proteins. It is different from DNA also due to the difference in one nitrogen basis as uracil. The thymine, the nitrogen basis that is only present in DNA is replaced with uracil to form RNA coding. The uracil also contains the same features as thymine has in DNA strains. Uracil makes a double H-bond with the adenine but does not contain CH4 group which is present in thymine.
 
        
        
        
The correct answer is - the variable.
With the experiment, in the way that Dan had decided to perform it, the fertilizer is the variable, as in one of the parts with strawberries he uses fertilizer, while in the other part he doesn't uses fertilizer.
While this kind of experiment may give Dan some answers, and he might notice differences, still he would have to be more detailed in the experiment to see for sure if the fertilizer is the thing that makes some of the strawberries grow better than the others.
Dan should also put all of the strawberries at places that would receive the same amount of light, experience the same weather conditions, receive the same amount of water, and to be planted in a soil of the same quality. Only like this, after putting the fertilizer, Dan can now if it makes any changes or not.