The Geologic Time Scale Is Often Subdivided on the Basis

question 19

Multiple Choice

The geologic time scale is often subdivided on the basis of ____.

• A) ​the appearance of different radioactive isotopes in different strata
• B) ​levels of background extinction
• C) ​periods of mass extinction
• D) ​the appearance of new species
• E) ​climate change

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Definitions:

Gram-variable

Pertaining to bacteria that do not consistently stain either as Gram-positive or Gram-negative because of their cell wall composition variations.

Opaqueness

The quality of being difficult to see through or understand, often used to describe materials that are not transparent or clear communications.

Decant

The process of gently pouring liquid from one container to another to separate it from sediment or other particles at the bottom.

Clarity

The quality of being clear, understandable, and transparent in expression, thought, or presentation.