Answer:
Thymine and uracil or adenine have two hydrogen bonds between them, whereas guanine and cytosine have three.
Theories are often the best explanations of natural phenomena we currently have. Yet, what one has to realize is that science is ever changing. That is why (B) is the correct answer, as new examinations, experiments, and discoveries could change some of these well-accepted theories. There is no way to "harm science" with viable observations and discoveries so (A) is incorrect. Answer (D) is also wrong since there is no assurance that a theory will never change in the future as they are merely accepted hypotheses. Answer (C) is not the best answer since theories are usually well supported and wouldn't be veritable if every examination proved flaws.
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