The matching of each situation to the step in the urine formation process where the problem lies are as follows:
- Step 1: Stella's urine contains protein due to inadequate filtration.
- Step 2: High toxin levels in the blood are due to Secretion. 
- Step 3: Increased Metabolic wastes are due to inadequate Reabsorption. 
- Step 4: The presence of vital Vitamins in urine is due to inadequate Reabsorption. 
Thus, Step 1 belongs to filtration, Step 2 belongs to secretion, and Steps 3 and 4 belong to reabsorption. 
<h3>What is the important function of Nephron?</h3>
The important function of the nephron may include the removal of all waste products through urine, secretion of numerous substances, excess water from the blood, etc. 
Therefore, it is well described above. 
To learn more about Nephron, refer to the link:
brainly.com/question/26062461
#SPJ1
 
        
             
        
        
        
Answer:
B. Black fur
Explanation:
The last two options are normal to a bird.
 
        
             
        
        
        
Cells in your body work together, they form bones, and muscles. Cells, however cannot work alone, they must be able to work together. Each cell does a different thing.
        
                    
             
        
        
        
The wind is just strong enough to move the sand grains which were sorted by size by the wind. Heavier grains were left in place where as smaller grains were carried away. These grains kept moving till they were concentrated in one place usually up a hill. The grains climb the flat slope on the windward side and then fall off the steep side. The dunes may migrate slowly as this process continues, the grains at the upwind side climb the dune with the help of the wind and then fall down the downwind side.<span>
</span>