1.DNA, ___, is found in the cell nucleus in the form of very long and thin molecules consisting of two spiral strands.

2.Potential dehydration is ___ that a land animal faces.

3.Before every presidential election in the United States, the statisticians try to guess the proportion of the population that ___ for each candidate.

4.Although thunder and lightning are produced at the same time, light waves travel faster ___, so we see the lightning before we hear the thunder.

5.All the committee members said the lecture was ___ a second time.

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