False.
The layering is usually thin.
They develop on the undersides of leaves.
Oxygen is a vital element within cellular respiration. An intrinsic part of the cellular respiration cycle is the transfer or electrons through the electron transport chain, and at the end of it exists the mitochondria, in which electrons are donated to the Oxygen and combine with hydrogen ions to form water.
Fish poop.
Tropical white beaches get their pearly white color from the excrement of fish far off of the coast which eat coral and other things that reside on the ocean floor. When they eat they swallow some sand into their mouths as well, and process it with the food they just ate. Their stomachs can't really digest the sand, tiny minute rocks essentially, and thus turn their color white. Or the rock forming the sand can be naturally pigmented a whitish tone as well.
The pH scale measures the concentration of how acidic or basic something is. The lower the number below 7, is acidic. Above 7 is basic. 7 is waters purest form.