While We Can Use Molecular Clocks Based on Molecular Sequence

question 68

Multiple Choice

While we can use molecular clocks based on molecular sequence data to estimate the times at which various lineages diverged, we ultimately need the _____ to calibrate the clocks.

• A)fossil record
• B)character states
• C)sister groups
• D)transitional forms
• E)DNA sequences

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Definitions:

Unconditioned Response

An automatic, innate reaction to a stimulus without prior learning or conditioning.

Positive Reinforcers

In behavioral psychology, stimuli that, when presented following a behavior, increase the likelihood of that behavior being repeated.

Negative Reinforcers

In behavioral psychology, an unpleasant stimulus whose removal leads to an increase in the likelihood that a preceding behavior will be repeated in the future.

Negative Reinforcement

A type of operant conditioning that strengthens a behavior by removing an unpleasant stimulus when the behavior occurs.