Test: Why Do We Fall Ill- 1 - Class 9 MCQ

Peptic ulcers were caused by stress, poor dietary habits.

• Encephalitis is a term used to describe inflammation of the brain. This condition causes problems with the brain and spinal cord function.
• The inflammation causes the brain to swell, which leads to changes in the person’s neurologic condition, including mental confusion and seizures.

• Chewing of tobacco may cause long term effects on an individual. It increases the risk for leukoplakia which is a precursor to oral cancer.
• Chewing tobacco has been known to cause cancer, particularly of the mouth and throat.

Diseases where microbes are immediate causes are called infectious diseases. Microbes can spread in a community and thereby spread the disease. 
Example: Tuberculosis, common cold, AIDS, etc.

Typhoid is caused by Salmonella typhi, which is a bacteria. All other diseases are caused by viruses.

• Malaria spreads when a mosquito becomes infected with the disease after biting an infected person, and the infected mosquito then bites a non-infected person.
• The malaria parasites enter that person's bloodstream and travel to the liver. When the parasites mature, they leave the liver and infect red blood cells.

• Mosquitos cause more human suffering than any other organism. Mosquitoes act as a vector for bacteria and viruses, responsible for diseases such as malaria, dengue, encephalitis and yellow fever etc.
• When mosquitoes bite a human it causes severe skin irritation through an allergic reaction to the mosquitoes saliva, this is what causes the red bump and itching.

• Human African trypanosomiasis, also known as sleeping sickness, is a vector-borne parasitic disease.
• It is caused by infection with protozoan parasites belonging to the genus Trypanosoma.

• AIDS ( acquired immunodeficiency syndrome)  don't spread by hugs or by handshakes. There are only a few ways you can get infected with HIV/AIDS.
• AIDS can be spread by sexual contact, breastfeeding, blood transfusion.