Which of the Following Kinds of Molecules Is Thought to Have

question 21

Multiple Choice

Which of the following kinds of molecules is thought to have been absent from the primitive reducing atmosphere?

• A)Water vapor (H₂O)
• B)Carbon dioxide (CO₂)
• C)Oxygen (O₂)
• D)Nitrogen (N₂)

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Definitions:

Fear

Conditioned response to stimuli associated with painful events; motivates avoidance of aversive events.

Pain

An unpleasant sensory and emotional experience associated with actual or potential tissue damage.

Escape

A type of behavior where an individual learns to perform an action to terminate an ongoing, unpleasant stimulus or situation.

Punisher

A stimulus that reduces the likelihood of the behavior that it follows.