If a substance can be separated by physical means and it’s not the same throughout , what is it

If a substance can be separated by physical means and it is not the same throughout,  it would be

A heterogeneous mixture.

Step-by-step explanation:

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.