Answer:
50%
Explanation:
This question involves a single gene with two alleles W and w in puppies. According to the question, the genotype of the parent organisms are Ww. In a cross between the two parents i.e. Ww × Ww, the following gametes will be produced by each parent: W and w. 
Using these gametes in a punnet square (see attached image), the following genotype of offsprings will be produced: WW, Ww, Ww, ww. Hence, based on this question, the percentage of puppies that would have the same genotype as the parents, Ww are 1/2 × 100% = 50%. 
 
        
             
        
        
        
It carries oxygen throughout the body
        
                    
             
        
        
        
Answer:
Firstly, the partial pressure of nitrogen (78%) is crucial to breathing purposes. Without this pressure, the lungs will burst and animals cannot survive. 
Secondly, nitrogen is required for the formation of amino acids (building blocks of proteins) and other organic compounds that are necessary for the survival of living organisms. Principally, in the atmosphere, nitrogen is present in the form of molecular nitrogen (N2). N2 is fixed by nitrogen-fixing bacteria that form nitrates and nitrites. These molecules are then used in biochemical processes to produce proteins (amino acids) and other organic compounds. In the absence of nitrogen, these processes could become seize of limited significantly thus affecting life overall.
Thirdly, nitrogen and its derivatives act as greenhouse gases that maintain the Earth's temperature within a range that supports life. Yes, the increased abundance of nitrous oxides is not good because of acid rain and other issues, however, still, the presence of nitrogen is important for life on this planet.