Can anyone answer this ( What has four wheels and flies?)

What are you doing this summer? fr !

Ar 5)when providing general information about an artwork, how is the title indicated? a)"title of artwork" b)title of artwork c)title of artwork d)title of artwork 6)select the term that refers to what the artwork is made of. a)iconography b)medium c)form d)context

The merode altarpiece by robert campin in what way did this painting make art history?