Answer:
the first wave of extinction may be related to rapid cooling at the end of the Ordovician Period, and the second phase is widely regarded as having been caused by the sea-level fall associated with the glaciation.
First question is - Why do we have limestone? Formed from this type of sediment are biological sedimentary rocks. Their biological organ is often revealed in the rock fossils. Some limestones can form by direct precipitation of calcium carbonate from marine or fresh water. (The second question is) - What do iron bands mean? The rocks are "banded" because the iron minerals deposited in alternating bands with silica and sometimes shale. The banding might have resulted from seasonal changes in organism activity steel mill. Most iron ore is used to make steel. Here a steel slab is being cut to length in a steel mill.
Long term: I could either help a species have more genetic variation or wipe out an entire species. Short term: it could decrease food resources for other species.
Puffapod (if this is for Harry Potter )
