[Solved] Any blanks or parentheses in row or column labels are changed to underscore characters in defined names. Sea Level: The average height of the ocean's surface between high and low tide, used as a reference point for measuring elevation or depth. Calcium Carbonate: A chemical compound with the formula CaCO3, found in rocks such as limestone, chalk, and marble, and is the main component of shells of marine organisms. Chalk Formation: A type of limestone characterized by its fine, white, porous structure, formed from the accumulation of microorganisms' calcite shells. Microscopic Organisms: Tiny life forms, not visible to the naked eye, including bacteria, protozoa, and certain types of fungi and algae.