One of the most common mistakes that occur with articles is using “a” or “an” with plural or uncountable nouns (a students-countable plural and an humor- uncountable). In case plural countabe you should use many or dehinite article 'the' if it is something specific. Now let us first indentify the countable and uncountabe in the example sentences.
Heart (C)Sense (C&U), circulation(U), space (C&U) , Jet Jag (C), heartburn(U)
In the example there is noun which can be consifered specific.So you will find the things easy now.
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