Why Did Natural Selection Favor the Use of Thymine as a Base

question 90

Multiple Choice

Why did natural selection favor the use of thymine as a base in DNA instead of uracil even though uracil was presumably present in RNA, when it served as the genetic material during the early evolution of life?

• A)Thymine was more stable.
• B)Thymine paired better with adenine than did uracil.
• C)Retention of uracil as a DNA base would make it hard to tell whether a uracil was supposed to be at a particular site or whether it resulted from damage to cytosine.
• D)Thymine is resistant to all chemical treatments.
• E)Retention of uracil as a DNA base would make it hard to tell whether a uracil was supposed to be at a particular site or whether it resulted from damage to guanine.

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