Floridaâs tract of coral reefs has the honor of being the third-largest barrier reef ecosystem in the world. However, it could soon be a thing of the past, as the acidification of the oceanâs water is dissolving it faster than it can rebuild.
index (plural indexes or indices) 1  An alphabetical listing of items and their location. The index of a book lists words or expressions and the pages of the book upon which they are to be found. 2  The index finger; the forefinger. 3  A movable finger on a gauge, scale, etc.
An index fossil is organisms that is a signature for certain geographical eras. Index fossils are a charting of time that is used to describe other organisms found in thatâ¦ time era. The fossils were found in the stones that are determinations by carbon indexing and therefore are index fossils.