Telephones made it easier for people too communicate with each other in different areas or across the world
Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters. It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal, and fecal debris.
Pollution, Habitat Removal/Alteration, and Climate Change.
Around the blue ish purple range