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Whether it is giving financial donations, raising money for us, getting involved in our campaigns, volunteering, or being advocates for us, your support means everything to us.
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Please explain the use of comma before "your support mean..."
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It separates the "whether" clause from the main clause. It corresponds to a natural pause in speech, or in the "mental speech" of reading. Commas like this are "simple" to understand because they correspond to obvious divisions of the sentence. I wouldn't try to make it more complicated than it is (unless you are interested in very technical punctuation theory).

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Jigneshbharati Whether it is giving financial donations, raising money for us, getting involved in our campaigns, volunteering, or being advocates for us, your support means everything to us.
Lymphoma Action | Privacy policy and cookies
Please explain the use of comma before "your support mean..."

Whether it is giving financial donations, raising money for us, getting involved in our campaigns, volunteering, or being advocates for us is a subordinate clause attached in front of the main clause your support means everything to us, and as such it is separated by a comma from the main clause .