In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

[EX Q]: Alcohol is high in calories - it supplies _ calories per gram and no nutrients worth mentioning.
[EX A]: seven

[EX Q]: Many comets have _ tails.
[EX A]: two

[EX Q]: Comets really have _ visible tails.
[EX A]:
two