a lawn is a piece of land covered with grass & lori uses fertilizer on her lawn & if fertilizer is used on a land, then the runoff from that land will contain fertilizer ->  the runoff from the lawn will contain fertilizer  the runoff from the lawn will contain fertilizer & a lake is a kind of body of water & runoff flows across land and ends in bodies of water ->  the runoff from the lawn containing fertilizer can flow and end in the lake  a lake is a kind of body of water & algae is found in bodies of water ->  algae can be found in lake  the runoff from the lawn containing fertilizer can flow and end in the lake & algae can be found in lake & fertilizers have a positive impact on algae growth -> the population of algae in the lake will increase because of the fertilizer in the runoff