The answer is A. Oligotrophic lakes are clear and hence
have little vegetation in them (hence no net primary production) that
could initiate the process of eutrophication. Eutrophication is brought about when bacteria
break down the high amount of organic matter hence reduce the oxygen supply in
the waters.
<span>The correct answer to the question, 'which of the following scenarios is representative of how agricultural practice can affect the environment' is A. Option A is chosen because it is the only option that refer to another environment which is different from that of the farm. When fertilizers are washed to nearby ponds as a result of erosion, it causes a lot of negative changes in the pond. For instance, the chemicals in the fertilizer can be poisonous to some of the smaller organisms in the pond, this will result in the death of these organisms. Fertilizer run off can also cause excessive growth of plants such as algae in the pond. This may block out the light necessary for the survival of the organisms in the ponds and may also reduce the amount of oxygen available to the organisms living in the pond.</span>
B. Sunlight doesn't reach the bottom of lakes..
