Which of the following may have a significant adverse impact upon the successful completion of an international project? (Select THREE).

Different time zones significantly complicate scheduling meetings, real-time collaboration, and establishing consistent working hours across international teams, leading to communication delays.

International travel costs can quickly escalate, impacting project budgets and potentially limiting essential face-to-face interactions or site visits necessary for successful project execution.

Co-location of resources is often a benefit for project efficiency, not an inherent adverse impact; its absence might be a challenge, but co-location itself is not negative.

While a poor project plan can have an adverse impact, 'The project plan' itself is a tool for success, not an inherent challenge unique to international projects.

Scheduled vacations are a normal part of any project and, while they require planning, are not a significant adverse impact unique to international projects compared to the other options.

Language barriers impede clear communication among international team members, stakeholders, and vendors, leading to misunderstandings, errors, and delays in project progress.