Government programs to reduce acid rain have resulted in cleaner emissions from u.s. industries in recent years. as a result, the sulfate concentration in rainwater has declined significantly. but the sulfate concentration in some lakes is showing little, if any, change. why might this be true?

This is true because certain manufacturing companies and other industries still donot comply with the governmental regulations and release the toxic wastes containing sulfates, into the water bodies. This contaminates them and the maximum allowed sulfate level of the water body exceeds its limit. 

Each cell has an identical set of DNA (chromosomes), and this DNA is also identical to that of the parent cell. If the cell cycle is not carefully controlled, it can cause a disease called cancer, which causes cell division to happen too fast.