(i)
Since every element of
(ii)
Since all the elements of
(iii)
Since all the students of class XI of one school are contained in that school, so,
(iv)
Since all the circles in a plane are not contained in the set of circles in the same plane with radius 1 unit, so,
(v)
Since the triangles in a plane is not the rectangle in that plane, so,
(vi)
Since all the equilateral triangles in a plane are contained in the set of all the triangles in a plane, so,
(vii)
Since all the even natural numbers are also integers, so,