Why do We Fall Ill : CBSE Class 9 IX Science In This Presentation include Revision Notes of Class 9 Science Why do we fall ill. Health is a state of complete physical, mental and social well-being of an individual. Health is often affected by diseases. Disease is the unhealthy condition caused by microorganisms, improper diet or it is inherited. “Disease” literally means being uncomfortable. A person affected by the disease will have improper functioning of the organ systems. Different symptoms which could be established during the diseased condition include headache, cough, loose motion and wounds with pus. For more information visit below links: youtube video link:https://youtu.be/FGf1Z4ADpDM Youtube Channel Link: https://www.youtube.com/channel/UCPiuJvuyMVFSwcIdBCTpTyQ Website Link: http://www.dronstudy.com Facebook Page:- https://www.facebook.com/dronstudy/?ref=hl