Answer:
3) they lose energy at a varying rate - is the correct answer.
Radioactive decay is defined as the process by which an unstable atomic nucleus loses its energy by emitting radiations. The decay is random and cannot be predicted earlier.
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Answer:
Overreacts to an antigen.
Explanation:
Thats what an allergy is if you think about it
 
        
             
        
        
        
No, because two creatures with similar niches can evolve similar traits and appearances despite not having a common ancestor.