Answer:
Hypoxia or low levels of oxygen
Explanation:
One of the negative impacts of eutrophication and increased algal growth is a loss of available oxygen, known as hypoxia. These anoxic conditions can kill fish and other aquatic organisms such as amphibians.
First blank space is endocrine system and the second blank is hormones
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.
