Which of the following are homogeneous in nature?

[C] (i) and (iv)
Option (I) Ice and (IV) Air are homogeneous in nature as their particles are not clearly visible. The entire mass of a homogeneous mixture has a uniform composition. There is no visible boundary of separation between its various components, e.g., ice, air, sugar solution, brass, etc. The entire mass of a heterogeneous mixture does not have a uniform composition. There are visible boundaries of separation between its various components, e.g., soil, wood, blood, etc.