Given below are two statements:
Statement I: The value of the parameter "Biochemical Oxygen Demand (BOD)" is important for survival of aquatic life.
Statement II: The optimum value of BOD is 6.5 ppm.
In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I says that the value of the parameter "Biochemical Oxygen Demand (BOD)" is important for survival of aquatic life. This is true. BOD measures the amount of dissolved oxygen consumed by microorganisms in the biological decomposition of organic matter in water. A high BOD indicates a large amount of organic pollutants, which depletes dissolved oxygen and threatens aquatic life. Therefore, monitoring BOD is indeed important for the survival of aquatic organisms.

Statement II says that the optimum value of BOD is 6.5 ppm. This is false. The value of 6.5 ppm is actually associated with the optimum pH of water or is sometimes confused with dissolved oxygen levels, not BOD. Clean water typically has a BOD of less than 5 ppm. A BOD value of 6.5 ppm would indicate moderately polluted water. The lower the BOD, the cleaner the water and the better conditions for aquatic life.

Therefore, the correct answer is Option (1): Statement I is true but Statement II is false.