The three layers of purification present in the filtration tank are ma

1.	The three layers of purification present in the filtration tank are made up of ____, ___ and ____.
Answer» <html><body><a href="https://interviewquestions.tuteehub.com/tag/top-1422115" style="font-weight:bold;" target="_blank" title="Click to know more about TOP">TOP</a>: <a href="https://interviewquestions.tuteehub.com/tag/fine-989069" style="font-weight:bold;" target="_blank" title="Click to know more about FINE">FINE</a> sand <a href="https://interviewquestions.tuteehub.com/tag/middle-1096062" style="font-weight:bold;" target="_blank" title="Click to know more about MIDDLE">MIDDLE</a> : <a href="https://interviewquestions.tuteehub.com/tag/coarse-421433" style="font-weight:bold;" target="_blank" title="Click to know more about COARSE">COARSE</a> sand <a href="https://interviewquestions.tuteehub.com/tag/bottom-401202" style="font-weight:bold;" target="_blank" title="Click to know more about BOTTOM">BOTTOM</a> : Gravel</body></html>

The three layers of purification present in the filtration tank are made up of __, _ and ____.