One word answer is Mutation nothing is perfect but some bacteria also have changes from conjugation aka sex between bacteria even though they are asexual organisms
        
             
        
        
        
A. He should add shells that are different colors, but the same size and type, to the tank and observe which shells the hermit crabs choose.
Durning an experiment you need to keep everything the same but only change the certain things based on your theory. 
Such as how the student wanted to see if the color attracted the crab. If he had changed the size and type of the shell then the crab would have chosen the bigger one as they tend to grow into larger shells.
        
             
        
        
        
In biology, the biotic factors pertain to the living components of Earth while the abiotic factors are those non-living chemicals and physical factors. The only choice that is not an interaction between biotic and abiotic factors is the third choice, "C. male elk fighting over a female". 
        
                    
             
        
        
        
Answer:
Yes.
Explanation:
Yes, this change of conditions also change the analysis of the situation because the analysis is related to the environmental conditions. When the environmental condition for an organisms changed so it also change its presence in that environment. If there is plenty of resources such as water, food and space for living, the population of that organism will be higher in that region while on the other hand, if this organisms is moved to a place where the resources such as water, food and space is scarce then it will leads to decrease in population of that organisms so we can say that change in conditions also bring change in our analysis.