One lawn chair is made of aluminum and another is made of iron

And a) oxygen i believe

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).

A. burning woodcombustion is the process of burning something. make brainliest if correct