Iwill give u some coal emits sulfur when it is burned. why is this a problem? a. sulfur is black and coats surfaces with black dust. b. sulfur forms sulfur dioxide, which acts as an air pollutant. c. sulfur produces heat so it needs to remain in the coal. d. sulfur increases the greenhouse effect.

why is arctic sea ice important? arctic sea ice keeps the polar regions cool and moderate global climate. sea ice has a bright surface; 80 percent of the sunlight that strikes it is reflected back into space. as sea ice melts in the summer, it exposes the dark ocean surface.

it's c. elements are placed in rows based on how may valencies electrons have.