Water is the Universal Solvent so, it acts as a transport medium in the living things. As water has some other properties, it has several effects on non-living things too.
Well, it's a long question, I hope it helps, if not, then pm me
The main point here is discuss about the structure of the nucleus in eukaryotes as an example we can use animal nuclei. compared to eukaryotes prokaryotes have simplier structure. we can talk about the arrangement of DNA in chromosomes while in prokaryotes DNA is circular in the cytoplasm. this helps during cell division such as mitosis and meiosis. in prokaryotes division occurs by binary fission. this can be an advantage in order to know the difference in genetic material in eukaryotes while binary fission ensures that all cells are genetically identical to each other
Those fish species are removed/ weakened so the organisms that the fish eat have less natural predators and increase in population. They need to eat more kelp in order to sustain their population, resulting in a loss of kelp as there is suddenly more of a demand for it then the kelp can grow. All because the predators were removed from the food chain.