If you provide your contact details, you are not obliged to participate in any further research, but you may be asked whether you would like to.
Os byddwch yn darparu eich manylion cyswllt, nid oes rheidrwydd arnoch i gymryd rhan mewn unrhyw ymchwil bellach, ond efallai y gofynnir i chi a hoffech wneud hynny.