Which of the following are the colloidal materials present in domestic sewage?

Which of the following is a cyclic and zero waste procedure?

Products of organic farming are preferred because they are<br> </h2></div>

In which of the following year, the depletion of the ozone layer have been noticed?</h2></div>

What is Global Warming? Write their main five reasons.</h2></div>

BOD of eutrophied lake will be</h2></div>

What is 'Greenhouse effect'?</h2></div>

Which of the following is correct regarding 'El Nino' effect?</h2></div>