Why do people in cities suffer from viral fever, allergies etc.?

What are the effects of Noise pollution?

Which of the following substances is responsible for causing Minamata disease?

1. Lead
2. Fluorides
3. Arsenic
4. Mercury

Which of the following processes is responsible for the depletion of oxygen from the water body?

1. Biomagnification
2. Bioaccumulatiom
3. Eutrophication
4. Oxygen cycle