Constituents of ANY mixture can be separated by physical methods.
True
Not all mixtures can be separated by physical methods. It is often a lot easier to separate heterogeneous mixtures by physical methods like hand-picking and sieving.
But it becomes a lot more difficult to separate some homogeneous mixtures. Alloys like brass and steel, coffee or tea and many others are examples of homogeneous mixtures which are very difficult to separate using physical methods.