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.

Recognize the significance of elders in the continuation and interpretation of human experiences and knowledge.

Analyze reasons why the elderly may experience more severe side effects from prescription drugs.

Understand non-genetic factors that contribute to preventing cognitive impairment.

Comprehend the risks associated with polypharmacy in the elderly.

---

Definitions:

Papillae

Small, nipple-like projections on the surface of the tongue containing tastebuds or on the skin.

Hydrochloric Acid

A strong, corrosive acid that is a major component of gastric juice, aiding digestion by breaking down foods and killing microbes.

Nasogastric

Relating to or involving the nose and the stomach, especially a tube that goes from the nose to the stomach for feeding or medication.

Alimentary Canal

The whole passage along which food passes through the body from mouth to anus, including the esophagus, stomach, and intestines.