___
A. The average time it takes for half of a group to decay.
B. Half the time it takes for a group to decay.
C. Half an hour for an individual nucleus to decay.
D. Half of the carbon present in a living organism.
___
A. Because it was an example in the textbook.
Because he is using popcorn in a laboratory demonstration.
C. Because popcorn is a good analogy for half-lives.
D. Because popcorn is a carbon-based life form.
___
A. It is the only accurate isotope for radiometric dating.
B. It represents most of the carbon in living things.
C. It has a half-life of almost 50 billion years.
D. It is used to estimate the age of carbon-based life forms.
___
A. He is preparing to suggest an answer to the question that he has just asked.
B. He is trying to encourage the students to answer a difficult question.
C. He is expressing doubt about the concept that he has been discussing.
D. He is probing to see whether the students have understood the lecture so far.
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