Answer:
Divergent boundaries also form volcanic islands, which occur when the plates move apart to produce gaps that molten lava rises to fill. Current research indicates that complex convection within the Earth's mantle allows material to rise to the base of the lithosphere beneath each divergent plate boundary.
It is called magma when in is under the earths crust, but above the surface it is called lava. So the answer would be "B."
I believe you would first check the river to make sure it's polluted then you would have to check how/if the chemical plant is involved. Also see if other factors other than the chemical plant is contaminating the river.
I hope this helps!
Answer:
UMM do You have anwers i meand if You have A B C D
