Answer
There is a common difference of $2$ therefore the given terms form an arithmetic sequence.
Work Step by Step
The given terms can be terms of an arithmetic sequence if there is a common difference among consecutive terms.
Determine the difference between each pair of consecutive terms to obtain:
$4-2=2;
\\6-4=2;
\\8-6=2$
There is a common difference of $2$ therefore the given terms form an arithmetic sequence.