The answer is:  <span>D. The population of bluebirds will decrease, leading to an eventual decrease in the number of predators.
The unwanted </span><span>dumping of chemicals causes a decrease in the number of insects. The insects are eaten by bluebirds, but if there is not enough food for the bluebirds, they will die- decrease of birds. If there are less bluebirds, their predators will have less food, so many of them will also die.</span>
        
                    
             
        
        
        
The answer is A. 0.54. 
In a population p+q=1 (we have 2 alleles only). 
The question states that 0.21 of the population(21%) have short legs meaning they are q^2. 
So q=rad0.21=0.4582. 
And p=1-q=0.5417.
        
                    
             
        
        
        
<span>Electrical signals in the body are often based on ions because ions are charged particles</span>
        
             
        
        
        
A haploid cell is one that contains one set of complete chromosomes.
        
             
        
        
        
I know why farmers use fertilizers..... to provide nutrition for the plant