A base formed when an acid loses (donates) a proton is

in theory, limestone is composed principally of the compound calcium carbonate - caco3, but in reality this compound is deposited in conditions involving a number of other compounds as impurities so it ends up being a mixture of many compounds.

hope this : -)

tony (lordcaos066)

im doing test rn im going with 2 but ill give answer if itss wrong,   : )