Siltation is the pollution of water by fine particulate terrestrial clastic material, with a particle size dominated by silt or clay.
red tide is known as algal bloom. When the dinoflagellates and the bloom takes on 
red or brown color . 
 Ozone layer it is the Earth's stratospehere that is responsible for absorbing most of the sun's ultraviolet rays to protect us.
Global climate is an average pattern of variation in temperature, humidity, wind, precipitation, and other meteorological variables  in a given region over long periods of time...
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