Polar questions are marked by an interrogative marker in most cases, but not always.
The interrogative particle can be placed at the end of the sentence, or after the first constituent.
In some cases intonation is sufficient to mark a polar question.
Source: Fleury 2007
Source: Laverdure and Allard 1983: 159
Source: Laverdure and Allard 1983: 162
Source: Laverdure and Allard 1983: 202
Source: Laverdure and Allard 1983: 211