A large number of fish are suddenly found floating dead on a lake. There is no evidence of toxic dumping but you find an abundance of phytoplankton. Suggest a reason for the fish kill.

A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this? i) Lots of urea and phosphate fertilizer were used in the crops in the vicinity ii) The area was sprayed with DDT by an aircraft iii) The lake water turned green and stinky iv)Phytoplankton populations in the lake declined initially, thereby greatly reducing photosynthesis.

Read the passage People started trapping, posoning and killing sparrow s in large numbers.Several free fire zones were set up for shooting the sparrows. People would beat drums to scare the birds from landing, so the sparrow ere forced to keep glying until they dropped dead from fatigue. Sparrow nests were torn down, egges were broken and nesttling were killed .Non material rewardsand recoginition were offered to school, work uits and gvernment agencies in accrdance with the number of sparrows killed . Later some scientists who cut open the digestive system of deal sparrows found that three- fourth of the contents were of insects harmful for crops adn ony one fourth contained grains. The scientiffic findings showed that sparrow were basically beneficial birds for humans. Rather than being increased, crop yields after the campaign were substantially decreased. What is the reason for less yield in the fields ?

Read the passage People started trapping, posoning and killing sparrow s in large numbers.Several free fire zones were set up for shooting the sparrows. People would beat drums to scare the birds from landing, so the sparrow ere forced to keep glying until they dropped dead from fatigue. Sparrow nests were torn down, egges were broken and nesttling were killed .Non material rewardsand recoginition were offered to school, work uits and gvernment agencies in accrdance with the number of sparrows killed . Later some scientists who cut open the digestive system of deal sparrows found that three- fourth of the contents were of insects harmful for crops adn ony one fourth contained grains. The scientiffic findings showed that sparrow were basically beneficial birds for humans. Rather than being increased, crop yields after the campaign were substantially decreased. What is the loss caused due to the killing of sparrows ?

Read the passage People started trapping, posoning and killing sparrow s in large numbers.Several free fire zones were set up for shooting the sparrows. People would beat drums to scare the birds from landing, so the sparrow ere forced to keep glying until they dropped dead from fatigue. Sparrow nests were torn down, egges were broken and nesttling were killed .Non material rewardsand recoginition were offered to school, work uits and gvernment agencies in accrdance with the number of sparrows killed . Later some scientists who cut open the digestive system of deal sparrows found that three- fourth of the contents were of insects harmful for crops adn ony one fourth contained grains. The scientiffic findings showed that sparrow were basically beneficial birds for humans. Rather than being increased, crop yields after the campaign were substantially decreased. Why the government of China mobilized o hunt down the sparrows ?