Plural? (Sarcasm is made manifest as explicit indices of quotation)

[Palinkasocsi]

Dear Forum Users,

Look at the following:

Sarcasm is made manifest as explicit indices of quotation (that is/are even mimed by hand gesture), intonational misfits, etc.

My question is:

Which is better to use: the singular or the plural?

Logic would opt for the plural but if we referred to mimicry itself as a (single) notion, then the singular would be better.

What do you natives think?

Many thanks.

Palinkasocsi

[Mister Micawber]

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Change the number of the noun.
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Native English teacher at Mister Micawber's