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.
the answer is four hope this helps :)
Photosynthesis is a process that uses the soliare to produce chemical energy (glucose). This means that the algae living in the water require a supply of solar light, and for that it would be necessary that the water is clear so that the solar rays can pass and reach the algae.
In the case where these corals and algae live in a cloudy or muddy water, the sun's rays do not pass very well, and therefore the photosynthesis of these algae is altered.