write D if the following is Defined (well-defined) and U if Undefined(not well-define) set.

1.the set of integers from 1 to 20
2.the set of practice exercise in Math 7
3.the set of moon in the planet Mars
4.the set of two digits odd numbers
5.the set of cool-shirts in a store
6.the set of the places which belongs to the 7 wonder of the world
7.the set of middle ages audiences in a concert
8.the set of positive integer
9.the set of universe 2019 candidates
10.the set of flowering plants