Answer:
A great example is the peppered moths evolution. Since the Industrial Revolution the birch trees started to turn black from the soot. This casued all the white moths to be eaten from birds. The ones that were left to mate were black moths which favored the black gene. So overtime black moths became more common. They were naturaly selected based on color to survived and pass down their black colored genes.  
Explanation:
 
        
             
        
        
        
The circulatory system works with the muscular system because then the muscles will be able to get oxygenated blood for the muscles to continue moving properly
        
             
        
        
        
Answer:
The number of protons in the nucleus of an atom is its atomic number (Z). This is the defining trait of an element: Its value determines the identity of the atom. For example, any atom that contains six protons is the element carbon and has the atomic number 6, regardless of how many neutrons or electrons it may have.
 
        
                    
             
        
        
        
Answer: A
Explanation:
They recognize and bind to specific sequences of DNA, called restriction sites. Each restriction enzyme recognizes just one or a few restriction sites. When it finds its target sequence, a restriction enzyme will make a double-stranded cut in the DNA molecule.
  (Also I think you meant Restriction sites, not Recognition sites.)
Hope This Helps!