As Life Was First Evolving, What Molecule Is Thought to Have

question 79

Multiple Choice

As life was first evolving, what molecule is thought to have performed double duty as the genetic material and catalyst of chemical reactions?

• A)RNA
• B)proteins
• C)polypeptides
• D)DNA
• E)both proteins and polypeptides

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Definitions:

Seawater

The saltwater that makes up the oceans and seas, covering more than 70% of the Earth's surface, containing various salts and life forms.

Silica-rich Organisms

Organisms that produce silica (silicon dioxide) as part of their structure, such as diatoms and certain sponges.

Cross Bed Formation

The structures within sedimentary rocks that result from angled deposition due to wind or water currents, indicating the direction of flow.

Sediment Composition

The makeup or content of material particles that accumulate on the Earth's surface, which can range from organic matter to minerals and rocks.