Final answer:
Mountaintop removal mining exposes rock containing heavy metals and toxic chemicals into the environment, making the statement true.
Step-by-step explanation:
The statement is true. Mountaintop removal mining involves the removal of mountaintops to expose coal seams, resulting in the exposure of rock that contains heavy metals and other toxic chemicals. This mining practice has severe detrimental effects on the environment as it destroys habitats, buries streams, and contaminates groundwater.