The correct answer is '<span>Oxygen is used up as algae is decomposed, reducing the amount available to other organisms.</span>' The additional nutrients in the water will result in an algal bloom. These algae will result in drastic oxygen fluctuation, from oxygen rich conditions during the day as algae photosynthesize, to anoxic conditions during the night when the algae respire. However, the algal bloom will eventually deplete the available nutrients, resulting in a vast algal die off. The decomposing algae result in anoxic conditions, and the effects are sometimes very obvious, with fish gasping for breath and dying. 
        
             
        
        
        
Increasing the stimulation up to the maximal stimulus
        
             
        
        
        
Answer:
Answer:
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Primary consumers are  those animals that depend on or they eat primary producers.
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Secondary consumers are those that eat mainly primary consumers.
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Explanation:
Primary Consumer: A primary consumer is an organism that directly eat primary producer ( plants). They are usually herbivores that eats autotrophic plants, autotrophic plants produce food through photosynthesis. Primary consumer are heterotrophic.
Example: Goat, cow and rabbit.
Secondary consumers: Secondary consumers depends mainly on primary consumers for their food  requirement. Secondary consumers are carnivores  as well as omnivores.
Example;  Owls, bears, lions and humans etc.