Answer:
A. They have different genetic sequences but are found in the same location on a chromosome.
Explanation:
In genetics, alleles are the variant form of a gene. According to Mendel, there are usually two alleles for most genes except for few cases where there are multiple alleles. Each allele of a pair is contributed by each parent during sexual reproduction. For example, in a gene Tt, the alleles are T for tallness and t for shortness.
Alleles of the same gene are related in such a way that they have different genetic sequences but are found in the same location on a chromosome. The different genetic sequences makes them alternative form of each other. 
 
        
             
        
        
        
Evolution would be the answer you may be looking for.
        
             
        
        
        
Answer:
The organisms homeostasis
 
        
             
        
        
        
Answer:
4
Explanation:
How do (sensory) receptors send messages to the brain?
Via (sensory) neurons
 
        
             
        
        
        
The statement that highlights and describes in detail the key features of an aquatic animal would be produce qualitative data analysis as we will describe its external features such as color size etc.