Which energy source would provide the cheapest electricity for a factory?

Why do leaves change color in the fall? green pigments break down and no longer mask the color of chlorophyll. chlorophyll breaks down and no longer masks the colors of other pigments. red- and yellow-colored pigments grow and mask green-colored chlorophyll. green-colored chlorophyll breaks down and turns red and yellow.

Why do we perceive objects as retaining their brightness under different lighting levels?

When lactate builds up in a runners muscles it causes a burning sensation what causes this to occur