Need help with International Accounting, please explain briefly. Thanks.

1. Please explain a tax inversion and the factors that impact a companys decision to process a tax inversion.

2. The earliest inversions were usually in tax haven countries. The companies subsequently relocated their headquarters to Europe. Why did these companies decide to move headquarters to European countries?

3. Most recent inversions either meet a substantial activity test or are accomplished through mergers. What companies are the most likely targets for these types of inversions?