Can u give an example from a gmat question. Then I would glad to help you.

Generally you can differ among each, every, all.
each and every emphasise rather the individual person in a group and thus are singuar. the word all emphasises the whole group.

for example:
each student has a different explanation.
all students have different explanations.

Differences between each and every:

Furthermore each can be used in front of a verb and can be followed by of.

gmatdriller wrote:Please can someone assist in explaining which of the two sentences is better and why?

"the disappearing species of xyz bacteria had been found to inhabit
(i) all regions of the South-West United States.
(ii) every region of the South-West United States.

What grammatical function motivates the choice between "all" and "every" region?

Is this a GMAT question
Probably experts can help