Among the following, find.the number of correct statements?
Sea water and trees are big sinks for carbondioxide.
Geater the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) values, greater is the extent of pollution.
Lesser the threshold limit value (TLV), greater the toxicity
Ozone layer present in stratosphere acts as protective umbrella form hamful sunrays.
Flouride ion in drinking water is detected by using zirconium alizarin - S dye. The dye loses its colour in the presence of flouride.
Human ear can tolerate the sound upto the intensity 60 decibles.

Answer

6