Choose the best topic sentence for the following passage ? slow music can make you feel sad . upbeat music can make you feel happy . if you walk while listening to music , a song with faster beat can make you walk faster . a slow song can make you walk more slowly .

When a lake, river or other aquatic  system  becomes  eutrophic, it can have serious negative effects on other organisms like fish, birds and even people.if an algal bloom is so bad that it causes wide-spread death  in  the  water, the organisms that die will all sink to the bottom and start to decompose.