Define BOD. What is its significance in an aquatic ecosystem?</h2></div>

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

The result of ozone hole is</h2></div>

Name the unit which is used to measure the thickness of ozone layer?</h2></div>

The amount of biodegradable organic matter in sewage water can be estimated by measuring</h2></div>

Elements can be diagonsed by</h2></div>

Plume' refers to path of<span><br> </span></h2></div>

Organic farming does not include ________.</h2></div>