Which of the following is a correct statement?</h2></div>

How is the value of COD compared to BOD?

Denitrification is caused by</h2></div>

Which of the following gases is regarded as an atmospheric pollutant?</h2></div>

Farming without the use of chemicals as fertilizers, herbicides and pesticides is known <span>as…

Of the following, which is a greenhouse gas?</h2></div>

Which of the following waste contributes heavily to environmental pollution?

Overall the contribution of carbon dioxide to global warming is</h2></div>