Rule 607.5

If an object acquires a pair of linked abilities as part of the same effect, the abilities will be similarly linked to one another on that object even though they weren’t printed on that object. They can’t be linked to any other ability, regardless of what other abilities the object may currently have or may have had in the past. Example: Arc-Slogger has the ability “{R}, Exile the top ten cards of your library: Arc-Slogger deals 2 damage to any target.” Sisters of Stone Death has the ability “{B}{G}: Exile target creature blocking or blocked by Sisters of Stone Death” and the ability “{2}{B}: Put a creature card exiled with Sisters of Stone Death onto the battlefield under your control.” Quicksilver Elemental has the ability “{U}: Quicksilver Elemental gains all activated abilities of target creature until end of turn.” If a player has Quicksilver Elemental gain Arc-Slogger’s ability, activates it, then has Quicksilver Elemental gain Sisters of Stone Death’s abilities, activates the exile ability, and then activates the return-to-the-battlefield ability, only the creature card Quicksilver Elemental exiled with Sisters of Stone Death’s ability can be returned to the battlefield. Creature cards Quicksilver Elemental exiled with Arc-Slogger’s ability can’t be returned.

Find this number in the current Rules