Living in herd is a structural adaptation.
There are three different kinds of adaptations: behavioural, physiological and structural.
Adaptations help animals survive and their ecosystem. 
The second sentence does not sound correct but it seems correct to me (just not in grammar).
Hope it helped!
        
                    
             
        
        
        
I do believe the answer is B because since it is going through each phase, the DNA strand will continue to adjust itself as the cell moves making the strands split allowing themselves to create copies. Since DNA has to be connected with another strand that will fit, it will be able to multiply itself based on the pieces that are missing
        
             
        
        
        
<span>Similarities and Differences 
     There are many similarities and differences between the three domains. Bacteria and Archaea differ in how they gain energy. Bacteria gain energy either by being phototrophs, lithotrophs or organotrophs. One similarity between domain Archaea and domain Bacteria is that they both contain only prokaryotes while domain Eukarya only contains eukaryotes. Domain Archaea is the only domain that is sensitive to antibiotics. Another similarity between domain Bacteria and domain Eukarya is that Methionine is the first amino acid seen during protein synthesis while in domain Archaea, the first amino acid is Formylmethionine. The last major similarity between domain Archaea and domain Bacteria is that they do not contain any organelles while domain Eukarya does. A difference between all three domains is what their cell walls contain. A cell wall in domain Archaea has peptidoglycan. The organisms that have a cell wall in domain Eukarya, will have a cell wall made up of polysaccharides.</span>
        
             
        
        
        
I think it is carbohydrate metabolism
        
             
        
        
        
The best answer would be "research reasons why species change over long periods of time" 
if not i apologize but this is my best guess<span />